Therapy of autoimmune disease in a patient with an inadequate response to a tnf-alpha inhibitor

ABSTRACT

The present application describes therapy with antagonists which bind to B cell surface markers, such as CD20. In particular, the application describes the use of such antagonists to treat autoimmune disease in a mammal who experiences an inadequate response to a TNFα-inhibitor.

This is a continuation application which claims priority under 35 USC§120 to non-provisional application Ser. No. 10/818,765, filed Apr. 6,2004, which claims priority under 35 USC §119 to provisional applicationNo. 60/461,481 filed Apr. 9, 2003, the entire disclosures of which arehereby incorporated by reference.

FIELD OF THE INVENTION

The present invention concerns therapy with antagonists which bind to Bcell surface markers, such as CD20. In particular, the inventionconcerns the use of such antagonists to treat autoimmune disease in amammal who experiences an inadequate response to a TNFα-inhibitor.

BACKGROUND OF THE INVENTION

Lymphocytes are one of many types of white blood cells produced in thebone marrow during the process of hematopoiesis. There are two majorpopulations of lymphocytes: B lymphocytes (B cells) and T lymphocytes (Tcells). The lymphocytes of particular interest herein are B cells.

B cells mature within the bone marrow and leave the marrow expressing anantigen-binding antibody on their cell surface. When a naive B cellfirst encounters the antigen for which its membrane-bound antibody isspecific, the cell begins to divide rapidly and its progenydifferentiate into memory B cells and effector cells called “plasmacells”. Memory B cells have a longer life span and continue to expressmembrane-bound antibody with the same specificity as the original parentcell. Plasma cells do not produce membrane-bound antibody but insteadproduce the antibody in a form that can be secreted. Secreted antibodiesare the major effector molecule of humoral immunity.

The CD20 antigen (also called human B-lymphocyte-restricteddifferentiation antigen, Bp35) is a hydrophobic transmembrane proteinwith a molecular weight of approximately 35 kD located on pre-B andmature B lymphocytes (Valentine et al. J. Biol. Chem.264(19):11282-11287 (1989); and Einfeld et al. EMBO J. 7(3):711-717(1988)). The antigen is also expressed on greater than 90% of B cellnon-Hodgkin's lymphomas (NHL) (Anderson et al. Blood 63(6):1424-1433(1984)), but is not found on hematopoietic stem cells, pro-B cells,normal plasma cells or other normal tissues (Tedder et al. J. Immunol.135(2):973-979 (1985)). CD20 regulates an early step(s) in theactivation process for cell cycle initiation and differentiation (Tedderet al., supra) and possibly functions as a calcium ion channel (Tedderet al. J. Cell. Biochem. 14D:195 (1990)).

Given the expression of CD20 in B cell lymphomas, this antigen can serveas a candidate for “targeting” of such lymphomas. In essence, suchtargeting can be generalized as follows: antibodies specific to the CD20surface antigen of B cells are administered to a patient. Theseanti-CD20 antibodies specifically bind to the CD20 antigen of(ostensibly) both normal and malignant B cells; the antibody bound tothe CD20 surface antigen may lead to the destruction and depletion ofneoplastic B cells. Additionally, chemical agents or radioactive labelshaving the potential to destroy the tumor can be conjugated to theanti-CD20 antibody such that the agent is specifically “delivered” tothe neoplastic B cells. Irrespective of the approach, a primary goal isto destroy the tumor; the specific approach can be determined by theparticular anti-CD20 antibody which is utilized and, thus, the availableapproaches to targeting the CD20 antigen can vary considerably.

CD 19 is another antigen that is expressed on the surface of cells ofthe B lineage. Like CD20, CD 19 is found on cells throughoutdifferentiation of the lineage from the stem cell stage up to a pointjust prior to terminal differentiation into plasma cells (Nadler, L.Lymphocyte Typing II 2: 3-37 and Appendix, Renling et al. eds. (1986) bySpringer Verlag). Unlike CD20 however, antibody binding to CD19 causesinternalization of the CD19 antigen. CD19 antigen is identified by theHD237-CD19 antibody (also called the “B4” antibody) (Kiesel et al.Leukemia Research II, 12: 1119 (1987)), among others. The CD19 antigenis present on 4-8% of peripheral blood mononuclear cells and on greaterthan 90% of B cells isolated from peripheral blood, spleen, lymph nodeor tonsil. CD19 is not detected on peripheral blood T cells, monocytesor granulocytes. Virtually all non-T cell acute lymphoblastic leukemias(ALL), B cell chronic lymphocytic leukemias (CLL) and B cell lymphomasexpress CD19 detectable by the antibody B4 (Nadler et al. J. Immunol.131:244 (1983); and Nadler et al. in Progress in Hematology Vol. XII pp.187-225. Brown, E. ed. (1981) by Grune & Stratton, Inc).

Additional antibodies which recognize differentiation stage-specificantigens expressed by cells of the B cell lineage have been identified.Among these are the B2 antibody directed against the CD21 antigen; B3antibody directed against the CD22 antigen; and the J5 antibody directedagainst the CD10 antigen (also called CALLA). See U.S. Pat. No.5,595,721 issued Jan. 21, 1997 (Kaminski et al.).

The rituximab (RITUXAN®) antibody is a genetically engineered chimericmurine/human monoclonal antibody directed against the CD20 antigen.Rituximab is the antibody called “C2B8” in U.S. Pat. No. 5,736,137issued Apr. 7, 1998 (Anderson et al.). RITUXAN® is indicated for thetreatment of patients with relapsed or refractory low-grade orfollicular, CD20 positive, B cell non-Hodgkin's lymphoma. In vitromechanism of action studies have demonstrated that RITUXAN® binds humancomplement and lyses lymphoid B cell lines through complement-dependentcytotoxicity (CDC) (Reff et al. Blood 83(2):435-445 (1994)).Additionally, it has significant activity in assays forantibody-dependent cellular cytotoxicity (ADCC). More recently, RITUXAN®has been shown to have anti-proliferative effects in tritiated thymidineincorporation assays and to induce apoptosis directly, while otheranti-CD19 and CD20 antibodies do not (Maloney et al. Blood 88(10):637a(1996)). Synergy between RITUXAN® and chemotherapies and toxins has alsobeen observed experimentally. In particular, RITUXAN® sensitizesdrug-resistant human B cell lymphoma cell lines to the cytotoxic effectsof doxorubicin, CDDP, VP-16, diphtheria toxin and ricin (Demidem et al.Cancer Biotherapy & Radiopharmaceuticals 12(3):177-186 (1997)). In vivopreclinical studies have shown that RITUXAN® depletes B cells from theperipheral blood, lymph nodes, and bone marrow of cynomolgus monkeys,presumably through complement and cell-mediated processes (Reff et al.Blood 83(2):435-445 (1994)).

Patents and patent publications concerning CD20 antibodies include U.S.Pat. Nos. 5,776,456, 5,736,137, 6,399,061, and 5,843,439, as well as USpatent appln nos. US 2002/0197255A1 and US 2003/0021781A1 (Anderson etal.); U.S. Pat. No. 6,455,043B1 and WO00/09160 (Grillo-Lopez, A.);WO00/27428 (Grillo-Lopez and White); WO00/27433 (Grillo-Lopez andLeonard); WO00/44788 (Braslawsky et al.); WO01/10462 (Rastetter, W.);WO01/10461 (Rastetter and White); WO01/10460 (White and Grillo-Lopez);US appln no. US2002/0006404 and WO02/04021 (Hanna and Hariharan); USappln no. US2002/0012665 A1 and WO01/74388 (Hanna, N.); US appln no.US2002/0009444A1, and WO01/80884 (Grillo-Lopez, A.); WO01/97858 (White,C.); US appln no. US2002/0128488A1 and WO02/34790 (Reff, M.);WO02/060955 (Braslawsky et al.); WO2/096948 (Braslawsky et al.);WO02/079255 (Reff and Davies); U.S. Pat. No. 6,171,586B1, and WO98/56418(Lam et al.); WO98/58964 (Raju, S.); WO99/22764 (Raju, S.); WO99/51642,U.S. Pat. No. 6,194,551B1, U.S. Pat. No. 6,242,195B1, U.S. Pat. No.6,528,624B1 and U.S. Pat. No. 6,538,124 (Idusogie et al.); WO00/42072(Presta, L.); WO00/67796 (Curd et al.); WO01/03734 (Grillo-Lopez etal.); US appln no. US 2002/0004587A1 and WO01/77342 (Miller and Presta);US appln no. US2002/0197256 (Grewal, I.); U.S. Pat. Nos. 6,090,365B1,6,287,537B1, 6,015,542, 5,843,398, and 5,595,721, (Kaminski et al.);U.S. Pat. Nos. 5,500,362, 5,677,180, 5,721,108, and 6,120,767(Robinsonet al.); U.S. Pat. No. 6,410,391B1 (Raubitschek et al.); U.S. Pat. No.6,224,866B1 and WO00/20864 (Barbera-Guillem, E.); WO01/13945(Barbera-Guillem, E.); WO00/67795 (Goldenberg); WO00/74718 (Goldenbergand Hansen); WO00/76542 (Golay et al.); WO01/72333 (Wolin andRosenblatt); U.S. Pat. No. 6,368,596B1 (Ghetie et al.); US Appln no.US2002/0041847A1, (Goldenberg, D.); US Appln no. US2003/0026801A1(Weiner and Hartmann); WO02/102312 (Engleman, E.), each of which isexpressly incorporated herein by reference. See, also, U.S. Pat. No.5,849,898 and EP appln no. 330,191 (Seed et al.); U.S. Pat. No.4,861,579 and EP332,865A2 (Meyer and Weiss); and WO95/03770 (Bhat etal.).

Publications concerning therapy with Rituximab include: Perrotta andAbuel “Response of chronic relapsing ITP of 10 years duration toRituximab” Abstract # 3360 Blood 10(1) (part 1-2): p. 88B (1998); Stasiet al. “Rituximab chimeric anti-CD20 monoclonal antibody treatment foradults with chronic idopathic thrombocytopenic purpura” Blood98(4):952-957 (2001); Matthews, R. “Medical Heretics” New Scientist (7Apr., 2001); Leandro et al. “Clinical outcome in 22 patients withrheumatoid arthritis treated with B lymphocyte depletion” Ann Rheum Dis61:833-888 (2002); Leandro et al. “Lymphocyte depletion in thrumatoidarthritis: early evidence for safety, efficacy and dose response.Arthritis and Rheumatism 44(9): S370 (2001); Leandro et al. “An openstudy of B lymphocyte depletion in systemic lupus erythematosus”,Arthritis & Rheumatism 46(1):2673-2677 (2002); Edwards and Cambridge“Sustained improvement in rheumatoid arthritis following a protocoldesigned to deplete B lymphocytes” Rhematology 40:205-211 (2001);Edwards et al. “B-lymphocyte depletion therapy in rheumatoid arthritisand other autoimmune disorders” Biochem. Soc. Trans. 30(4):824-828(2002); Edwards et al. “Efficacy and safety of Rituximab, a B-celltargeted chimeric monoclonal antibody: A randomized, placebo controlledtrial in patients with rheumatoid arthritis. Arthritis and Rheumatism46(9): S197 (2002); Levine and Pestronk “IgM antibody-relatedpolyneuropathies: B-cell depletion chemotherapy using Rituximab”Neurology 52: 1701-1704 (1999); DeVita et al. “Efficacy of selective Bcell blockade in the treatment of rheumatoid arthritis” Arthritis &Rheum 46:2029-2033 (2002); Hidashida et al. “Treatment ofDMARD-Refractory rheumatoid arthritis with rituximab.” Presented at theAnnual Scientific Meeting of the American College of Rheumatology;October 24-29; New Orleans, La. 2002; Tuscano, J. “Successful treatmentof Infliximab-refractory rheumatoid arthritis with rituximab” Presentedat the Annual Scientific Meeting of the American College ofRheumatology; October 24-29; New Orleans, La. 2002.

Rhematoid arthritis (RA) is an autoimmune disorder of unknown etiology.Most RA patients suffer a chronic course of disease that, even withtherapy, may result in progressive joint destruction, deformity,disability and even premature death. More than 9 million physicianvisits and more than 250,000 hospitalizations per year result from RA.The goals of RA therapy are to prevent or control joint damage, preventloss of function and decrease pain. Initial therapy of RA usuallyinvolves administration of one or more of the following drugs:nonsteroidal antiinflammatory drugs (NSAIDs), glucocorticoid (via jointinjection), and low-dose prednisone. See “Guidelines for the managementof rheumatoid arthritis” Arthritis & Rheumatism 46(2): 328-346(February, 2002). The majority of patients with newly diagnosed RA arestarted with disease-modifying antirheumatic drug (DMARD) therapy within3 months of diagnosis. DMARDs commonly used in RA are hydroxycloroquine,sulfasalazine, methotrexate, leflunomide, etanercept, infliximab (plusoral and subcutaneous methrotrexate), azathioprine, D-penicillamine,Gold (oral), Gold (intramuscular), minocycline, cyclosporine,Staphylococcal protein A immunoadsorption.

Because the body produces tumor necrosis factor alpha (TNFα) during RA,TNFα inhibitors have used for therapy of that disease.

Etanercept (ENBREL®) is an injectable drug approved in the US fortherapy of active RA. Etanercept binds to TNFα and serves to remove mostTNFα from joints and blood, thereby preventing TNFα from promotinginflammation and other symptoms of rheumatoid arthritis. Etanercept isan “immunoadhesin” fusion protein consisting of the extracellular ligandbinding portion of the human 75 kD (p75) tumor necrosis factor receptor(TNFR) linked to the Fc portion of a human IgG1. The drug has beenassociated with negative side effects including serious infections andsepsis, nervous system disorders such as multiple sclerosis (MS). See,e.g., www.remicade-infliximab.com/pages/enbrel_embrel.html

Infliximab, sold under the trade name REMICADE®, is animmune-suppressing drug prescribed to treat RA and Crohn's disease.Infliximab is a chimeric monoclonal antibody that binds to TNFα andreduces inflammation in the body by targeting and binding to TNFα whichproduces inflammation. Infliximab has been linked to a fatal reactionssuch as heart failure and infections including tuberculosis as well asdemyelination resulting in MS.

In December 2002, Abbott Laboratories received FDA approval to marketadalimumab (HUMIRA™), previously known as D2E7. Adalimumab is a humanmonoclonal antibody that binds to TNFα and is approved for reducing thesigns and symptoms and inhibiting the progression of structural damagein adults with moderately to severely active RA who have hadinsufficient response to one or more traditional disease modifyingDMARDs.

SUMMARY OF THE INVENTION

The present invention provides, in a first aspect, a method of treatingan autoimmune disease in a mammal who experiences an inadequate responseto a TNFα-inhibitor, comprising administering to the mammal atherapeutically effective amount of an antagonist which binds to a Bcell surface marker.

For instance, the invention provides a method of treating rheumatoidarthritis in a mammal who experiences an inadequate response to aTNFα-inhibitor, comprising administering to the mammal a therapeuticallyeffective amount of an antibody that binds to CD20.

The invention also concerns a method of reducing the risk of a negativeside effect selected from the group consisting of an infection, heartfailure and demyelination, comprising administering to a mammal with anautoimmune disease a therapeutically effective amount of an antagonistwhich binds to a B cell surface marker.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS I. Definitions

For the purposes herein, “tumor necrosis factor alpha (TNFα)” refers toa human TNFα molecule comprising the amino acid sequence as described inPennica et al., Nature, 312:721 (1984) or Aggarwal et al., JBC, 260:2345(1985).

A “TNFα inhibitor” herein is an agent that inhibits, to some extent, abiological function of TNFα, generally through binding to TNFα andneutralizing its activity. Examples of TNF inhibitors specificallycontemplated herein are Etanercept (ENBREL®), Infliximab (REMICADE®) andAdalimumab (HUMIRA™).

The term “inadequate response to a TNFα-inhibitor” refers to aninadequate response to previous or current treatment with aTNFα-inhibitor because of toxicity and/or inadequate efficacy. Theinadequate response can be assessed by a clinician skilled in treatingthe disease in question.

A mammal who experiences “toxicity” from previous or current treatmentwith the TNFα-inhibitor experiences one or more negative side-effectsassociated therewith such as infection (especially serious infections),congestive heart failure, demyelination (leading to multiple sclerosis),hypersensitivity, neurologic events, autoimmunity, non-Hodgkin'slymphoma, tuberculosis (TB), autoantibodies, etc.

A mammal who experiences “inadequate efficacy” continues to have activedisease following previous or current treatment with a TNFα-inhibitor.For instance, the patient may have active disease activity after 1 monthor 3 months of therapy with the TNFα-inhibitor.

By “reducing the risk of a negative side effect” is meant reducing therisk of a side effect resulting from therapy with the antagonist thatbinds to a B-cell surface marker to a lower extent than that seen withtherapy with a TNFα-inhibitor. Such side effects include infection(especially serious infections), heart failure, and demyelination(multiple sclerosis), etc.

A “B cell surface marker” herein is an antigen expressed on the surfaceof a B cell which can be targeted with an antagonist which bindsthereto. Exemplary B cell surface markers include the CD10, CD19, CD20,CD21, CD22, CD23, CD24, CD37, CD40, CD53, CD72, CD73, CD74, CDw75,CDw76, CD77, CDw78, CD79a, CD79b, CD80, CD81, CD82, CD83, CDw84, CD85and CD86 leukocyte surface markers. The B cell surface marker ofparticular interest is preferentially expressed on B cells compared toother non-B cell tissues of a mammal and may be expressed on bothprecursor B cells and mature B cells. In one embodiment, the marker isone, like CD20 or CD 19, which is found on B cells throughoutdifferentiation of the lineage from the stem cell stage up to a pointjust prior to terminal differentiation into plasma cells. The preferredB cell surface markers herein is CD20.

The “CD20” antigen is a ˜35 kDa, non-glycosylated phosphoprotein foundon the surface of greater than 90% of B cells from peripheral blood orlymphoid organs. CD20 is expressed during early pre-B cell developmentand remains until plasma cell differentiation. CD20 is present on bothnormal B cells as well as malignant B cells. Other names for CD20 in theliterature include “B-lymphocyte-restricted antigen” and “Bp35”. TheCD20 antigen is described in Clark et al. PNAS (USA) 82:1766 (1985), forexample.

An “autoimmune disease” herein is a disease or disorder arising from anddirected against an individual's own tissues. Examples of autoimmunediseases or disorders include, but are not limited to arthritis(rheumatoid arthritis, juvenile rheumatoid arthritis, osteoarthritis,psoriatic arthritis), psoriasis, dermatitis,polymyositis/dermatomyositis, toxic epidermal necrolysis, systemicscleroderma and sclerosis, responses associated with inflammatory boweldisease, Crohn's disease, ulcerative colitis, respiratory distresssyndrome, adult respiratory distress syndrome (ARDS), meningitis,encephalitis, uveitis, colitis, glomerulonephritis, allergic conditions,eczema, asthma, conditions involving infiltration of T cells and chronicinflammatory responses, atherosclerosis, autoimmune myocarditis,leukocyte adhesion deficiency, systemic lupus erythematosus (SLE),juvenile onset diabetes, multiple sclerosis, allergic encephalomyelitis,immune responses associated with acute and delayed hypersensitivitymediated by cytokines and T-lymphocytes, tuberculosis, sarcoidosis,granulomatosis including Wegener's granulomatosis, agranulocytosis,vasculitis (including ANCA), aplastic anemia, Diamond Blackfan anemia,immune hemolytic anemia including autoimmune hemolytic anemia (AIHA),pernicious anemia, pure red cell aplasia (PRCA), Factor VIII deficiency,hemophilia A, autoimmune neutropenia, pancytopenia, leukopenia, diseasesinvolving leukocyte diapedesis, central nervous system (CNS)inflammatory disorders, multiple organ injury syndrome, mysatheniagravis, antigen-antibody complex mediated diseases, anti-glomerularbasement membrane disease, anti-phospholipid antibody syndrome, allergicneuritis, Bechet disease, Castleman's syndrome, Goodpasture's syndrome,Lambert-Eaton Myasthenic Syndrome, Reynaud's syndrome, Sjorgen'ssyndrome, Stevens-Johnson syndrome, solid organ transplant rejection,graft versus host disease (GVHD), pemphigoid bullous, pemphigus,autoimmune polyendocrinopathies, Reiter's disease, stiff-man syndrome,giant cell arteritis, immune complex nephritis, IgA nephropathy, IgMpolyneuropathies or IgM mediated neuropathy, idiopathic thrombocytopenicpurpura (ITP), thrombotic throbocytopenic purpura (TTP), autoimmunethrombocytopenia, autoimmune disease of the testis and ovary includingautoimmune orchitis and oophoritis, primary hypothyroidism; autoimmuneendocrine diseases including autoimmune thyroiditis, chronic thyroiditis(Hashimoto's Thyroiditis), subacute thyroiditis, idiopathichypothyroidism, Addison's disease, Grave's disease, autoimmunepolyglandular syndromes (or polyglandular endocrinopathy syndromes),Type I diabetes also referred to as insulin-dependent diabetes mellitus(IDDM) and Sheehan's syndrome; autoimmune hepatitis, lymphoidinterstitial pneumonitis (HIV), bronchiolitis obliterans(non-transplant) vs NSIP, Guillain-Barre' syndrome, large vesselvasculitis (including polymyalgia rheumatica and giant cell (Takayasu's)arteritis), medium vessel vasculitis (including Kawasaki's disease andpolyarteritis nodosa), ankylosing spondylitis, Berger's disease (IgAnephropathy), rapidly progressive glomerulonephritis, primary biliarycirrhosis, Celiac sprue (gluten enteropathy), cryoglobulinemia,amyotrophic lateral sclerosis (ALS), coronary artery disease etc.

An “antagonist” is a molecule which, upon binding to a B cell surfacemarker, destroys or depletes B cells in a mammal and/or interferes withone or more B cell functions, e.g. by reducing or preventing a humoralresponse elicited by the B cell. The antagonist preferably is able todeplete B cells (i.e. reduce circulating B cell levels) in a mammaltreated therewith. Such depletion may be achieved via various mechanismssuch antibody-dependent cell-mediated cytotoxicity (ADCC) and/orcomplement dependent cytotoxicity (CDC), inhibition of B cellproliferation and/or induction of B cell death (e.g. via apoptosis).Antagonists included within the scope of the present invention includeantibodies, synthetic or native sequence peptides and small moleculeantagonists which bind to the B cell marker, optionally conjugated withor fused to a cytotoxic agent. The preferred antagonist comprises anantibody.

“Antibody-dependent cell-mediated cytotoxicity” and “ADCC” refer to acell-mediated reaction in which nonspecific cytotoxic cells that expressFc receptors (FcRs) (e.g. Natural Killer (NK) cells, neutrophils, andmacrophages) recognize bound antibody on a target cell and subsequentlycause lysis of the target cell. The primary cells for mediating ADCC, NKcells, express FcγRIII only, whereas monocytes express FcγRI, FcγRII andFcγRIII. FcR expression on hematopoietic cells in summarized is Table 3on page 464 of Ravetch and Kinet, Annu. Rev. Immunol 9:457-92 (1991). Toassess ADCC activity of a molecule of interest, an in vitro ADCC assay,such as that described in U.S. Pat. No. 5,500,362 or 5,821,337 may beperformed. Useful effector cells for such assays include peripheralblood mononuclear cells (PBMC) and Natural Killer (NK) cells.Alternatively, or additionally, ADCC activity of the molecule ofinterest may be assessed in vivo, e.g., in a animal model such as thatdisclosed in Clynes et al. PNAS (USA) 95:652-656 (1998).

“Human effector cells” are leukocytes which express one or more FcRs andperform effector functions. Preferably, the cells express at leastFcγRIII and carry out ADCC effector function. Examples of humanleukocytes which mediate ADCC include peripheral blood mononuclear cells(PBMC), natural killer (NK) cells, monocytes, cytotoxic T cells andneutrophils; with PBMCs and NK cells being preferred.

The terms “Fc receptor” or “FcR” are used to describe a receptor thatbinds to the Fc region of an antibody. The preferred FcR is a nativesequence human FcR. Moreover, a preferred FcR is one which binds an IgGantibody (a gamma receptor) and includes receptors of the FcγRI, FcγRII,and FcγRIII subclasses, including allelic variants and alternativelyspliced forms of these receptors. FcγRII receptors include FcγRIIA (an“activating receptor”) and FcγRIIB (an “inhibiting receptor”), whichhave similar amino acid sequences that differ primarily in thecytoplasmic domains thereof. Activating receptor FcγRIIA contains animmunoreceptor tyrosine-based activation motif (ITAM) in its cytoplasmicdomain. Inhibiting receptor FcγRIIB contains an immunoreceptortyrosine-based inhibition motif (ITIM) in its cytoplasmic domain. (seeDaëron, Annu. Rev. Immunol. 15:203-234 (1997)). FcRs are reviewed inRavetch and Kinet, Annu. Rev. Immunol 9:457-92 (1991); Capel et al.,Immunomethods 4:25-34 (1994); and de Haas et al., J. Lab. Clin. Med.126:330-41 (1995). Other FcRs, including those to be identified in thefuture, are encompassed by the term “FcR” herein. The term also includesthe neonatal receptor, FcRn, which is responsible for the transfer ofmaternal IgGs to the fetus (Guyer et al., J. Immunol. 117:587 (1976) andKim et al., J. Immunol. 24:249 (1994)).

“Complement dependent cytotoxicity” or “CDC” refer to the ability of amolecule to lyse a target in the presence of complement. The complementactivation pathway is initiated by the binding of the first component ofthe complement system (C1q) to a molecule (e.g. an antibody) complexedwith a cognate antigen. To assess complement activation, a CDC assay,e.g. as described in Gazzano-Santoro et al., J. Immunol. Methods 202:163(1996), may be performed.

“Growth inhibitory” antagonists are those which prevent or reduceproliferation of a cell expressing an antigen to which the antagonistbinds. For example, the antagonist may prevent or reduce proliferationof B cells in vitro and/or in vivo.

Antagonists which “induce apoptosis” are those which induce programmedcell death, e.g. of a B cell, as determined by standard apoptosisassays, such as binding of annexin V, fragmentation of DNA, cellshrinkage, dilation of endoplasmic reticulum, cell fragmentation, and/orformation of membrane vesicles (called apoptotic bodies).

The term “antibody” herein is used in the broadest sense andspecifically covers intact monoclonal antibodies, polyclonal antibodies,multispecific antibodies (e.g. bispecific antibodies) formed from atleast two intact antibodies, and antibody fragments so long as theyexhibit the desired biological activity.

“Antibody fragments” comprise a portion of an intact antibody,preferably comprising the antigen-binding or variable region thereof.Examples of antibody fragments include Fab, Fab′, F(ab′)₂, and Fvfragments; diabodies; linear antibodies; single-chain antibodymolecules; and multispecific antibodies formed from antibody fragments.

“Native antibodies” are usually heterotetrameric glycoproteins of about150,000 daltons, composed of two identical light (L) chains and twoidentical heavy (H) chains. Each light chain is linked to a heavy chainby one covalent disulfide bond, while the number of disulfide linkagesvaries among the heavy chains of different immunoglobulin isotypes. Eachheavy and light chain also has regularly spaced intrachain disulfidebridges. Each heavy chain has at one end a variable domain (V_(H))followed by a number of constant domains. Each light chain has avariable domain at one end (V_(L)) and a constant domain at its otherend; the constant domain of the light chain is aligned with the firstconstant domain of the heavy chain, and the light-chain variable domainis aligned with the variable domain of the heavy chain. Particular aminoacid residues are believed to form an interface between the light chainand heavy chain variable domains.

The term “variable” refers to the fact that certain portions of thevariable domains differ extensively in sequence among antibodies and areused in the binding and specificity of each particular antibody for itsparticular antigen. However, the variability is not evenly distributedthroughout the variable domains of antibodies. It is concentrated inthree segments called hypervariable regions both in the light chain andthe heavy chain variable domains. The more highly conserved portions ofvariable domains are called the framework regions (FRs). The variabledomains of native heavy and light chains each comprise four FRs, largelyadopting a β-sheet configuration, connected by three hypervariableregions, which form loops connecting, and in some cases forming part of,the β-sheet structure. The hypervariable regions in each chain are heldtogether in close proximity by the FRs and, with the hypervariableregions from the other chain, contribute to the formation of theantigen-binding site of antibodies (see Kabat et al., Sequences ofProteins of Immunological Interest, 5th Ed. Public Health Service,National Institutes of Health, Bethesda, Md. (1991)). The constantdomains are not involved directly in binding an antibody to an antigen,but exhibit various effector functions, such as participation of theantibody in antibody dependent cellular cytotoxicity (ADCC).

Papain digestion of antibodies produces two identical antigen-bindingfragments, called “Fab” fragments, each with a single antigen-bindingsite, and a residual “Fc” fragment, whose name reflects its ability tocrystallize readily. Pepsin treatment yields an F(ab′)₂ fragment thathas two antigen-binding sites and is still capable of cross-linkingantigen.

“Fv” is the minimum antibody fragment which contains a completeantigen-recognition and antigen-binding site. This region consists of adimer of one heavy chain and one light chain variable domain in tight,non-covalent association. It is in this configuration that the threehypervariable regions of each variable domain interact to define anantigen-binding site on the surface of the V_(H)−V_(L) dimer.Collectively, the six hypervariable regions confer antigen-bindingspecificity to the antibody. However, even a single variable domain (orhalf of an Fv comprising only three hypervariable regions specific foran antigen) has the ability to recognize and bind antigen, although at alower affinity than the entire binding site.

The Fab fragment also contains the constant domain of the light chainand the first constant domain (CH1) of the heavy chain. Fab′ fragmentsdiffer from Fab fragments by the addition of a few residues at thecarboxy terminus of the heavy chain CH1 domain including one or morecysteines from the antibody hinge region. Fab′-SH is the designationherein for Fab′ in which the cysteine residue(s) of the constant domainsbear at least one free thiol group. F(ab′)₂ antibody fragmentsoriginally were produced as pairs of Fab′ fragments which have hingecysteines between them. Other chemical couplings of antibody fragmentsare also known.

The “light chains” of antibodies (immunoglobulins) from any vertebratespecies can be assigned to one of two clearly distinct types, calledkappa (κ) and lambda (λ), based on the amino acid sequences of theirconstant domains.

Depending on the amino acid sequence of the constant domain of theirheavy chains, antibodies can be assigned to different classes. There arefive major classes of intact antibodies: IgA, IgD, IgE, IgG, and IgM,and several of these may be further divided into subclasses (isotypes),e.g., IgG1, IgG2, IgG3, IgG4, IgA, and IgA2. The heavy-chain constantdomains that correspond to the different classes of antibodies arecalled α, δ, ε, γ, and μ, respectively. The subunit structures andthree-dimensional configurations of different classes of immunoglobulinsare well known.

“Single-chain Fv” or “scFv” antibody fragments comprise the V_(H) andV_(L) domains of antibody, wherein these domains are present in a singlepolypeptide chain. Preferably, the Fv polypeptide further comprises apolypeptide linker between the V_(H) and V_(L) domains which enables thescFv to form the desired structure for antigen binding. For a review ofscFv see Plückthun in The Pharmacology of Monoclonal Antibodies, vol.113, Rosenburg and Moore eds., Springer-Verlag, New York, pp. 269-315(1994).

The term “diabodies” refers to small antibody fragments with twoantigen-binding sites, which fragments comprise a heavy-chain variabledomain (V_(H)) connected to a light-chain variable domain (V_(L)) in thesame polypeptide chain (V_(H)-V_(L)). By using a linker that is tooshort to allow pairing between the two domains on the same chain, thedomains are forced to pair with the complementary domains of anotherchain and create two antigen-binding sites. Diabodies are described morefully in, for example, EP 404,097; WO 93/11161; and Hollinger et al.,Proc. Natl. Acad. Sci. USA, 90:6444-6448 (1993).

The term “monoclonal antibody” as used herein refers to an antibodyobtained from a population of substantially homogeneous antibodies,i.e., the individual antibodies comprising the population are identicalexcept for possible naturally occurring mutations that may be present inminor amounts. Monoclonal antibodies are highly specific, being directedagainst a single antigenic site. Furthermore, in contrast toconventional (polyclonal) antibody preparations which typically includedifferent antibodies directed against different determinants (epitopes),each monoclonal antibody is directed against a single determinant on theantigen. In addition to their specificity, the monoclonal antibodies areadvantageous in that they are synthesized by the hybridoma culture,uncontaminated by other immunoglobulins. The modifier “monoclonal”indicates the character of the antibody as being obtained from asubstantially homogeneous population of antibodies, and is not to beconstrued as requiring production of the antibody by any particularmethod. For example, the monoclonal antibodies to be used in accordancewith the present invention may be made by the hybridoma method firstdescribed by Kohler et al., Nature, 256:495 (1975), or may be made byrecombinant DNA methods (see, e.g., U.S. Pat. No. 4,816,567). The“monoclonal antibodies” may also be isolated from phage antibodylibraries using the techniques described in Clackson et al., Nature,352:624-628 (1991) and Marks et al., J. Mol. Biol., 222:581-597 (1991),for example.

The monoclonal antibodies herein specifically include “chimeric”antibodies (immunoglobulins) in which a portion of the heavy and/orlight chain is identical with or homologous to corresponding sequencesin antibodies derived from a particular species or belonging to aparticular antibody class or subclass, while the remainder of thechain(s) is identical with or homologous to corresponding sequences inantibodies derived from another species or belonging to another antibodyclass or subclass, as well as fragments of such antibodies, so long asthey exhibit the desired biological activity (U.S. Pat. No. 4,816,567;Morrison et al., Proc. Natl. Acad. Sci. USA, 81:6851-6855 (1984)).Chimeric antibodies of interest herein include “primatized” antibodiescomprising variable domain antigen-binding sequences derived from anon-human primate (e.g. Old World Monkey, such as baboon, rhesus orcynomolgus monkey) and human constant region sequences (U.S. Pat. No.5,693,780).

“Humanized” forms of non-human (e.g., murine) antibodies are chimericantibodies that contain minimal sequence derived from non-humanimmunoglobulin. For the most part, humanized antibodies are humanimmunoglobulins (recipient antibody) in which residues from ahypervariable region of the recipient are replaced by residues from ahypervariable region of a non-human species (donor antibody) such asmouse, rat, rabbit or nonhuman primate having the desired specificity,affinity, and capacity. In some instances, framework region (FR)residues of the human immunoglobulin are replaced by correspondingnon-human residues. Furthermore, humanized antibodies may compriseresidues that are not found in the recipient antibody or in the donorantibody. These modifications are made to further refine antibodyperformance. In general, the humanized antibody will comprisesubstantially all of at least one, and typically two, variable domains,in which all or substantially all of the hypervariable loops correspondto those of a non-human immunoglobulin and all or substantially all ofthe FRs are those of a human immunoglobulin sequence. The humanizedantibody optionally also will comprise at least a portion of animmunoglobulin constant region (Fc), typically that of a humanimmunoglobulin. For further details, see Jones et al., Nature321:522-525 (1986); Riechmann et al., Nature 332:323-329 (1988); andPresta, Curr. Op. Struct. Biol. 2:593-596 (1992).

The term “hypervariable region” when used herein refers to the aminoacid residues of an antibody which are responsible for antigen-binding.The hypervariable region comprises amino acid residues from a“complementarity determining region” or “CDR” (e.g. residues 24-34 (L1),50-56 (L2) and 89-97 (L3) in the light chain variable domain and 31-35(H1), 50-65 (H2) and 95-102 (H3) in the heavy chain variable domain;Kabat et al., Sequences of Proteins of Immunological Interest, 5th Ed.Public Health Service, National Institutes of Health, Bethesda, Md.(1991)) and/or those residues from a “hypervariable loop” (e.g. residues26-32 (L1), 50-52 (L2) and 91-96 (L3) in the light chain variable domainand 26-32 (H1), 53-55 (H2) and 96-101 (H3) in the heavy chain variabledomain; Chothia and Lesk J. Mol. Biol. 196:901-917 (1987)). “Framework”or “FR” residues are those variable domain residues other than thehypervariable region residues as herein defined.

An antagonist “which binds” an antigen of interest, e.g. a B cellsurface marker, is one capable of binding that antigen with sufficientaffinity and/or avidity such that the antagonist is useful as atherapeutic agent for targeting a cell expressing the antigen.

Examples of antibodies which bind the CD20 antigen include: “C2B8” whichis now called “rituximab” (“RITUXAN®”) (U.S. Pat. No. 5,736,137,expressly incorporated herein by reference); the yttrium-[90]-labeled2B8 murine antibody designated “Y2B8” (U.S. Pat. No. 5,736,137,expressly incorporated herein by reference); murine IgG2a “B1”optionally labeled with ¹³¹I to generate the “¹³¹I-B1” antibody(BEXXAR™) (U.S. Pat. No. 5,595,721, expressly incorporated herein byreference); murine monoclonal antibody “1F5” (Press et al. Blood69(2):584-591 (1987)); “chimeric 2H7 antibody” (U.S. Pat. No. 5,677,180,expressly incorporated herein by reference); “humanized 2H7 v16” (seebelow); huMax-CD20 (Genmab, Denmark); AME-133 (Applied MolecularEvolution); and monoclonal antibodies L27, G28-2, 93-1B3, B-C1 or NU-B2available from the International Leukocyte Typing Workshop (Valentine etal., In: Leukocyte Typing III (McMichael, Ed., p. 440, Oxford UniversityPress (1987)).

Examples of antibodies which bind the CD19 antigen include the anti-CD19antibodies in Hekman et al. Cancer Immunol. Immunother. 32:364-372(1991) and Vlasveld et al. Cancer Immunol. Immunother. 40:37-47 (1995);and the B4 antibody in Kiesel et al. Leukemia Research II, 12: 1119(1987).

The terms “rituximab” or “RITUXAN®” herein refer to the geneticallyengineered chimeric murine/human monoclonal antibody directed againstthe CD20 antigen and designated “C2B8” in U.S. Pat. No. 5,736,137,expressly incorporated herein by reference. The antibody is an IgG₁kappa immunoglobulin containing murine light and heavy chain variableregion sequences and human constant region sequences. Rituximab has abinding affinity for the CD20 antigen of approximately 8.0 nM.

Purely for the purposes herein, “humanized 2H7 v16” refers to anantibody comprising the variable light and variable heavy sequencesshown below.

Variable light-chain domain of hu2H7 v16

(SEQ ID NO: 1) DIQMTQSPSSLSASVGDRVTITCRASSSVSYMHWYQQKPGKAPKPLIYAPSNLASGVPSRESGSGSGTDFTLTISSLQPEDFATYYCQQWSFNPPTFGQG TKVEIKR

Variable heavy-chain domain of hu2H7 v16

(SEQ ID NO: 2) EVQLVESGGGLVQPGGSLRLSCAASGYTFTSYNMHWVRQAPGKGLEWVGAIYPGNGDTSYNQKFKGRFTISVDKSKNTLYLQMNSLRAEDTAVYYCARVVYYSNSYWYFDVWGQGTLVTVSS

Preferably humanized 2H7 v16 comprises the light chain amino acidsequence

(SEQ ID NO: 3) DIQMTQSPSSLSASVGDRVTITCRASSSVSYMHWYQQKPGKAPKPLIYAPSNLASGVPSRFSGSGSGTDFTLTISSLQPEDFATYYCQQWSFNPPTFGQGTKVEIKRTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGL SSPVTKSFNRGEC;

and heavy chain amino acid sequence

(SEQ ID NO: 4) EVQLVESGGGLVQPGGSLRLSCAASGYTFTSYNMHWVRQAPGKGLEWVGAIYPGNGDTSYNQKFKGRFTISVDKSKNTLYLQMNSLRAEDTAVYYCARVVYYSNSYWYFDVWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSP GK.

An “isolated” antagonist is one which has been identified and separatedand/or recovered from a component of its natural environment.Contaminant components of its natural environment are materials whichwould interfere with diagnostic or therapeutic uses for the antagonist,and may include enzymes, hormones, and other proteinaceous ornonproteinaceous solutes. In preferred embodiments, the antagonist willbe purified (1) to greater than 95% by weight of antagonist asdetermined by the Lowry method, and most preferably more than 99% byweight, (2) to a degree sufficient to obtain at least 15 residues ofN-terminal or internal amino acid sequence by use of a spinning cupsequenator, or (3) to homogeneity by SDS-PAGE under reducing ornonreducing conditions using Coomassie blue or, preferably, silverstain. Isolated antagonist includes the antagonist in situ withinrecombinant cells since at least one component of the antagonist'snatural environment will not be present. Ordinarily, however, isolatedantagonist will be prepared by at least one purification step.

“Mammal” for purposes of treatment refers to any animal classified as amammal, including humans, domestic and farm animals, and zoo, sports, orpet animals, such as dogs, horses, cats, cows, etc. Preferably, themammal is human.

“Treatment” refers to both therapeutic treatment and prophylactic orpreventative measures. Those in need of treatment include those alreadywith the disease or disorder as well as those in which the disease ordisorder is to be prevented. Hence, the mammal may have been diagnosedas having the disease or disorder or may be predisposed or susceptibleto the disease.

The expression “therapeutically effective amount” refers to an amount ofthe antagonist which is effective for preventing, ameliorating ortreating the autoimmune disease in question.

The term “immunosuppressive agent” as used herein for adjunct therapyrefers to substances that act to suppress or mask the immune system ofthe mammal being treated herein. This would include substances thatsuppress cytokine production, downregulate or suppress self-antigenexpression, or mask the MHC antigens. Examples of such agents include2-amino-6-aryl-5-substituted pyrimidines (see U.S. Pat. No. 4,665,077,the disclosure of which is incorporated herein by reference);nonsteroidal antiinflammatory drugs (NSAIDs); azathioprine;cyclophosphamide; bromocryptine; danazol; dapsone; glutaraldehyde (whichmasks the MHC antigens, as described in U.S. Pat. No. 4,120,649);anti-idiotypic antibodies for MHC antigens and MHC fragments;cyclosporin A; steroids such as glucocorticosteroids, e.g., prednisone,methylprednisolone, and dexamethasone; methotrexate (oral orsubcutaneous); hydroxycloroquine; sulfasalazine; leflunomide; cytokineor cytokine receptor antagonists including anti-interferon-γ, -β, or -αantibodies, anti-tumor necrosis factor-s antibodies (infliximab oradalimumab), anti-TNFα immunoahesin (etanercept), anti-tumor necrosisfactor-β antibodies, anti-interleukin-2 antibodies and anti-IL-2receptor antibodies; anti-LFA-1 antibodies, including anti-CD11a andanti-CD18 antibodies; anti-L3T4 antibodies; heterologous anti-lymphocyteglobulin; pan-T antibodies, preferably anti-CD3 or anti-CD4/CD4aantibodies; soluble peptide containing a LFA-3 binding domain (WO90/08187 published Jul. 26, 1990); streptokinase; TGF-β; streptodornase;RNA or DNA from the host; FK506; RS-61443; deoxyspergualin; rapamycin;T-cell receptor (Cohen et al., U.S. Pat. No. 5,114,721); T-cell receptorfragments (Offner et al., Science, 251: 430-432 (1991); WO 90/11294;Ianeway, Nature, 341: 482 (1989); and WO 91/01133); and T cell receptorantibodies (EP 340,109) such as T10B9.

The term “cytotoxic agent” as used herein refers to a substance thatinhibits or prevents the function of cells and/or causes destruction ofcells. The term is intended to include radioactive isotopes (e.g. At²¹¹,I¹³¹, I¹²⁵, Y⁹⁰, Re¹⁸⁶, Re¹⁸⁸, Sm¹⁵³, Bi²¹², P³² and radioactiveisotopes of Lu), chemotherapeutic agents, and toxins such as smallmolecule toxins or enzymatically active toxins of bacterial, fungal,plant or animal origin, or fragments thereof.

A “chemotherapeutic agent” is a chemical compound useful in thetreatment of cancer. Examples of chemotherapeutic agents includealkylating agents such as thiotepa and cyclosphosphamide (CYTOXAN™);alkyl sulfonates such as busulfan, improsulfan and piposulfan;aziridines such as benzodopa, carboquone, meturedopa, and uredopa;ethylenimines and methylamelamines including altretamine,triethylenemelamine, trietylenephosphoramide,triethylenethiophosphaoramide and trimethylolomelamine; nitrogenmustards such as chlorambucil, chlomaphazine, cholophosphamide,estramustine, ifosfamide, mechlorethamine, mechlorethamine oxidehydrochloride, melphalan, novembichin, phenesterine, prednimustine,trofosfamide, uracil mustard; nitrosureas such as carmustine,chlorozotocin, fotemustine, lomustine, nimustine, ranimustine;antibiotics such as aclacinomysins, actinomycin, authramycin, azaserine,bleomycins, cactinomycin, calicheamicin, carabicin, caminomycin,carzinophilin, chromomycins, dactinomycin, daunorubicin, detorubicin,6-diazo-5-oxo-L-norleucine, doxorubicin, epirubicin, esorubicin,idarubicin, marcellomycin, mitomycins, mycophenolic acid, nogalamycin,olivomycins, peplomycin, potfiromycin, puromycin, quelamycin,rodorubicin, streptonigrin, streptozocin, tubercidin, ubenimex,zinostatin, zorubicin; anti-metabolites such as methotrexate and5-fluorouracil (5-FU); folic acid analogues such as denopterin,methotrexate, pteropterin, trimetrexate; purine analogs such asfludarabine, 6-mercaptopurine, thiamiprine, thioguanine; pyrimidineanalogs such as ancitabine, azacitidine, 6-azauridine, carmofur,cytarabine, dideoxyuridine, doxifluridine, enocitabine, floxuridine,5-FU; androgens such as calusterone, dromostanolone propionate,epitiostanol, mepitiostane, testolactone; anti-adrenals such asaminoglutethimide, mitotane, trilostane; folic acid replenisher such asfrolinic acid; aceglatone; aldophosphamide glycoside; aminolevulinicacid; amsacrine; bestrabucil; bisantrene; edatraxate; defofamine;demecolcine; diaziquone; elfornithine; elliptinium acetate; etoglucid;gallium nitrate; hydroxyurea; lentinan; lonidamine; mitoguazone;mitoxantrone; mopidamol; nitracrine; pentostatin; phenamet; pirarubicin;podophyllinic acid; 2-ethylhydrazide; procarbazine; PSK®; razoxane;sizofiran; spirogermanium; tenuazonic acid; triaziquone; 2,2′,2″-trichorotriethylamine; urethan; vindesine; dacarbazine;mannomustine; mitobronitol; mitolactol; pipobroman; gacytosine;arabinoside (“Ara-C”); cyclophosphamide; thiotepa; taxoids, e.g.paclitaxel (TAXOL®, Bristol-Myers Squibb Oncology, Princeton, N.J.) anddoxetaxel (TAXOTERE®, Rhône-Poulenc Rorer, Antony, France);chlorambucil; gemcitabine; 6-thioguanine; mercaptopurine; methotrexate;platinum analogs such as cisplatin and carboplatin; vinblastine;platinum; etoposide (VP-16); ifosfamide; mitomycin C; mitoxantrone;vincristine; vinorelbine; navelbine; novantrone; teniposide; daunomycin;aminopterin; xeloda; ibandronate; CPT-11; topoisomerase inhibitor RFS2000; difluoromethylornithine (DMFO); retinoic acid; esperamicins;capecitabine; and pharmaceutically acceptable salts, acids orderivatives of any of the above. Also included in this definition areanti-hormonal agents that act to regulate or inhibit hormone action ontumors such as anti-estrogens including for example tamoxifen,raloxifene, aromatase inhibiting 4(5)-imidazoles, 4-hydroxytamoxifen,trioxifene, keoxifene, LY117018, onapristone, and toremifene (Fareston);and anti-androgens such as flutamide, nilutamide, bicalutamide,leuprolide, and goserelin; and pharmaceutically acceptable salts, acidsor derivatives of any of the above.

The term “cytokine” is a generic term for proteins released by one cellpopulation which act on another cell as intercellular mediators.Examples of such cytokines are lymphokines, monokines, and traditionalpolypeptide hormones. Included among the cytokines are growth hormonesuch as human growth hormone, N-methionyl human growth hormone, andbovine growth hormone; parathyroid hormone; thyroxine; insulin;proinsulin; relaxin; prorelaxin; glycoprotein hormones such as folliclestimulating hormone (FSH), thyroid stimulating hormone (TSH), andluteinizing hormone (LH); hepatic growth factor; fibroblast growthfactor; prolactin; placental lactogen; tumor necrosis factor-α and -β;mullerian-inhibiting substance; mouse gonadotropin-associated peptide;inhibin; activin; vascular endothelial growth factor; integrin;thrombopoietin (TPO); nerve growth factors such as NGF-β;platelet-growth factor; transforming growth factors (TGFs) such as TGF-αand TGF-β; insulin-like growth factor-I and -II; erythropoietin (EPO);osteoinductive factors; interferons such as interferon-α,-β, and -γ;colony stimulating factors (CSFs) such as macrophage-CSF (M-CSF);granulocyte-macrophage-CSF (GM-CSF); and granulocyte-CSF (G-CSF);interleukins (ILs) such as IL-1, IL-1α, IL-2, IL-3, IL-4, IL-5, IL-6,IL-7, IL-8, IL-9, IL-11, IL-12, IL-15; a tumor necrosis factor such asTNF-α or TNF-β; and other polypeptide factors including LIF and kitligand (KL). As used herein, the term cytokine includes proteins fromnatural sources or from recombinant cell culture and biologically activeequivalents of the native sequence cytokines.

The term “prodrug” as used in this application refers to a precursor orderivative form of a pharmaceutically active substance that is lesscytotoxic to tumor cells compared to the parent drug and is capable ofbeing enzymatically activated or converted into the more active parentform. See, e.g., Wilman, “Prodrugs in Cancer Chemotherapy” BiochemicalSociety Transactions, 14, pp. 375-382, 615th Meeting Belfast (1986) andStella et al., “Prodrugs: A Chemical Approach to Targeted DrugDelivery,” Directed Drug Delivery, Borchardt et al., (ed.), pp. 247-267,Humana Press (1985). The prodrugs of this invention include, but are notlimited to, phosphate-containing prodrugs, thiophosphate-containingprodrugs, sulfate-containing prodrugs, peptide-containing prodrugs,D-amino acid-modified prodrugs, glycosylated prodrugs,β-lactam-containing prodrugs, optionally substitutedphenoxyacetamide-containing prodrugs or optionally substitutedphenylacetamide-containing prodrugs, 5-fluorocytosine and other5-fluorouridine prodrugs which can be converted into the more activecytotoxic free drug. Examples of cytotoxic drugs that can be derivatizedinto a prodrug form for use in this invention include, but are notlimited to, those chemotherapeutic agents described above.

A “liposome” is a small vesicle composed of various types of lipids,phospholipids and/or surfactant which is useful for delivery of a drug(such as the antagonists disclosed herein and, optionally, achemotherapeutic agent) to a mammal. The components of the liposome arecommonly arranged in a bilayer formation, similar to the lipidarrangement of biological membranes.

II. Production of Antagonists

The methods and articles of manufacture of the present invention use, orincorporate, an antagonist which binds to a B cell surface marker.Accordingly, methods for generating such antagonists will be describedhere.

The B cell surface marker to be used for production of, or screeningfor, antagonist(s) may be, e.g., a soluble form of the antigen or aportion thereof, containing the desired epitope. Alternatively, oradditionally, cells expressing the B cell surface marker at their cellsurface can be used to generate, or screen for, antagonist(s). Otherforms of the B cell surface marker useful for generating antagonistswill be apparent to those skilled in the art. Preferably, the B cellsurface marker is the CD20 antigen.

While the preferred antagonist is an antibody, antagonists other thanantibodies are contemplated herein. For example, the antagonist maycomprise a small molecule antagonist optionally fused to, or conjugatedwith, a cytotoxic agent (such as those described herein). Libraries ofsmall molecules may be screened against the B cell surface marker ofinterest herein in order to identify a small molecule which binds tothat antigen. The small molecule may further be screened for itsantagonistic properties and/or conjugated with a cytotoxic agent.

The antagonist may also be a peptide generated by rational design or byphage display (see, e.g., WO98/35036 published 13 Aug. 1998). In oneembodiment, the molecule of choice may be a “CDR mimic” or antibodyanalogue designed based on the CDRs of an antibody. While such peptidesmay be antagonistic by themselves, the peptide may optionally be fusedto a cytotoxic agent so as to add or enhance antagonistic properties ofthe peptide.

A description follows as to exemplary techniques for the production ofthe antibody antagonists used in accordance with the present invention.

(i) Polyclonal Antibodies

Polyclonal antibodies are preferably raised in animals by multiplesubcutaneous (sc) or intraperitoneal (ip) injections of the relevantantigen and an adjuvant. It may be useful to conjugate the relevantantigen to a protein that is immunogenic in the species to be immunized,e.g., keyhole limpet hemocyanin, serum albumin, bovine thyroglobulin, orsoybean trypsin inhibitor using a bifunctional or derivatizing agent,for example, maleimidobenzoyl sulfosuccinimide ester (conjugationthrough cysteine residues), N-hydroxysuccinimide (through lysineresidues), glutaraldehyde, succinic anhydride, SOCl₂, or R¹N═C═NR, whereR and R¹ are different alkyl groups.

Animals are immunized against the antigen, immunogenic conjugates, orderivatives by combining, e.g., 100 μg or 5 μg of the protein orconjugate (for rabbits or mice, respectively) with 3 volumes of Freund'scomplete adjuvant and injecting the solution intradermally at multiplesites. One month later the animals are boosted with 1/5 to 1/10 theoriginal amount of peptide or conjugate in Freund's complete adjuvant bysubcutaneous injection at multiple sites. Seven to 14 days later theanimals are bled and the serum is assayed for antibody titer. Animalsare boosted until the titer plateaus. Preferably, the animal is boostedwith the conjugate of the same antigen, but conjugated to a differentprotein and/or through a different cross-linking reagent. Conjugatesalso can be made in recombinant cell culture as protein fusions. Also,aggregating agents such as alum are suitably used to enhance the immuneresponse.

(ii) Monoclonal Antibodies

Monoclonal antibodies are obtained from a population of substantiallyhomogeneous antibodies, i.e., the individual antibodies comprising thepopulation are identical except for possible naturally occurringmutations that may be present in minor amounts. Thus, the modifier“monoclonal” indicates the character of the antibody as not being amixture of discrete antibodies.

For example, the monoclonal antibodies may be made using the hybridomamethod first described by Kohler et al., Nature, 256:495 (1975), or maybe made by recombinant DNA methods (U.S. Pat. No. 4,816,567).

In the hybridoma method, a mouse or other appropriate host animal, suchas a hamster, is immunized as hereinabove described to elicitlymphocytes that produce or are capable of producing antibodies thatwill specifically bind to the protein used for immunization.Alternatively, lymphocytes may be immunized in vitro. Lymphocytes thenare fused with myeloma cells using a suitable fusing agent, such aspolyethylene glycol, to form a hybridoma cell (Goding, MonoclonalAntibodies: Principles and Practice, pp. 59-103 (Academic Press, 1986)).

The hybridoma cells thus prepared are seeded and grown in a suitableculture medium that preferably contains one or more substances thatinhibit the growth or survival of the unfused, parental myeloma cells.For example, if the parental myeloma cells lack the enzyme hypoxanthineguanine phosphoribosyl transferase (HGPRT or HPRT), the culture mediumfor the hybridomas typically will include hypoxanthine, aminopterin, andthymidine (HAT medium), which substances prevent the growth ofHGPRT-deficient cells.

Preferred myeloma cells are those that fuse efficiently, support stablehigh-level production of antibody by the selected antibody-producingcells, and are sensitive to a medium such as HAT medium. Among these,preferred myeloma cell lines are murine myeloma lines, such as thosederived from MOPC-21 and MPC-11 mouse tumors available from the SalkInstitute Cell Distribution Center, San Diego, Calif. USA, and SP-2 orX63-Ag8-653 cells available from the American Type Culture Collection,Rockville, Md. USA. Human myeloma and mouse-human heteromyeloma celllines also have been described for the production of human monoclonalantibodies (Kozbor, J. Immunol., 133:3001 (1984); Brodeur et al.,Monoclonal Antibody Production Techniques and Applications, pp. 51-63(Marcel Dekker, Inc., New York, 1987)).

Culture medium in which hybridoma cells are growing is assayed forproduction of monoclonal antibodies directed against the antigen.Preferably, the binding specificity of monoclonal antibodies produced byhybridoma cells is determined by immunoprecipitation or by an in vitrobinding assay, such as radioimmunoassay (RIA) or enzyme-linkedimmunoabsorbent assay (ELISA).

The binding affinity of the monoclonal antibody can, for example, bedetermined by the Scatchard analysis of Munson et al., Anal. Biochem.,107:220 (1980).

After hybridoma cells are identified that produce antibodies of thedesired specificity, affinity, and/or activity, the clones may besubcloned by limiting dilution procedures and grown by standard methods(Goding, Monoclonal Antibodies: Principles and Practice, pp. 59-103(Academic Press, 1986)). Suitable culture media for this purposeinclude, for example, D-MEM or RPMI-1640 medium. In addition, thehybridoma cells may be grown in vivo as ascites tumors in an animal.

The monoclonal antibodies secreted by the subclones are suitablyseparated from the culture medium, ascites fluid, or serum byconventional immunoglobulin purification procedures such as, forexample, protein A-Sepharose, hydroxylapatite chromatography, gelelectrophoresis, dialysis, or affinity chromatography.

DNA encoding the monoclonal antibodies is readily isolated and sequencedusing conventional procedures (e.g., by using oligonucleotide probesthat are capable of binding specifically to genes encoding the heavy andlight chains of murine antibodies). The hybridoma cells serve as apreferred source of such DNA. Once isolated, the DNA may be placed intoexpression vectors, which are then transfected into host cells such asE. coli cells, simian COS cells, Chinese Hamster Ovary (CHO) cells, ormyeloma cells that do not otherwise produce immunoglobulin protein, toobtain the synthesis of monoclonal antibodies in the recombinant hostcells. Review articles on recombinant expression in bacteria of DNAencoding the antibody include Skerra et al., Curr. Opinion in Immunol.,5:256-262 (1993) and Plückthun, Immunol. Revs., 130:151-188 (1992).

In a further embodiment, antibodies or antibody fragments can beisolated from antibody phage libraries generated using the techniquesdescribed in McCafferty et al., Nature, 348:552-554 (1990). Clackson etal., Nature, 352:624-628 (1991) and Marks et al., J. Mol. Biol.,222:581-597 (1991) describe the isolation of murine and humanantibodies, respectively, using phage libraries. Subsequent publicationsdescribe the production of high affinity (nM range) human antibodies bychain shuffling (Marks et al., Bio/technology, 10:779-783 (1992)), aswell as combinatorial infection and in vivo recombination as a strategyfor constructing very large phage libraries (Waterhouse et al., Nuc.Acids. Res., 21:2265-2266 (1993)). Thus, these techniques are viablealternatives to traditional monoclonal antibody hybridoma techniques forisolation of monoclonal antibodies.

The DNA also may be modified, for example, by substituting the codingsequence for human heavy- and light-chain constant domains in place ofthe homologous murine sequences (U.S. Pat. No. 4,816,567; Morrison, etal., Proc. Natl. Acad. Sci. USA, 81:6851 (1984)), or by covalentlyjoining to the immunoglobulin coding sequence all or part of the codingsequence for a non-immunoglobulin polypeptide.

Typically such non-immunoglobulin polypeptides are substituted for theconstant domains of an antibody, or they are substituted for thevariable domains of one antigen-combining site of an antibody to createa chimeric bivalent antibody comprising one antigen-combining sitehaving specificity for an antigen and another antigen-combining sitehaving specificity for a different antigen.

(iii) Humanized Antibodies

Methods for humanizing non-human antibodies have been described in theart. Preferably, a humanized antibody has one or more amino acidresidues introduced into it from a source which is non-human. Thesenon-human amino acid residues are often referred to as “import”residues, which are typically taken from an “import” variable domain.Humanization can be essentially performed following the method of Winterand co-workers (Jones et al., Nature, 321:522-525 (1986); Riechmann etal., Nature, 332:323-327 (1988); Verhoeyen et al., Science,239:1534-1536 (1988)), by substituting hypervariable region sequencesfor the corresponding sequences of a human antibody. Accordingly, such“humanized” antibodies are chimeric antibodies (U.S. Pat. No. 4,816,567)wherein substantially less than an intact human variable domain has beensubstituted by the corresponding sequence from a non-human species. Inpractice, humanized antibodies are typically human antibodies in whichsome hypervariable region residues and possibly some FR residues aresubstituted by residues from analogous sites in rodent antibodies.

The choice of human variable domains, both light and heavy, to be usedin making the humanized antibodies is very important to reduceantigenicity. According to the so-called “best-fit” method, the sequenceof the variable domain of a rodent antibody is screened against theentire library of known human variable-domain sequences. The humansequence which is closest to that of the rodent is then accepted as thehuman framework region (FR) for the humanized antibody (Sims et al., J.Immunol., 151:2296 (1993); Chothia et al., J. Mol. Biol., 196:901(1987)). Another method uses a particular framework region derived fromthe consensus sequence of all human antibodies of a particular subgroupof light or heavy chains. The same framework may be used for severaldifferent humanized antibodies (Carter et al., Proc. Natl. Acad. Sci.USA, 89:4285 (1992); Presta et al., J. Immunol., 151:2623 (1993)).

It is further important that antibodies be humanized with retention ofhigh affinity for the antigen and other favorable biological properties.To achieve this goal, according to a preferred method, humanizedantibodies are prepared by a process of analysis of the parentalsequences and various conceptual humanized products usingthree-dimensional models of the parental and humanized sequences.Three-dimensional immunoglobulin models are commonly available and arefamiliar to those skilled in the art. Computer programs are availablewhich illustrate and display probable three-dimensional conformationalstructures of selected candidate immunoglobulin sequences. Inspection ofthese displays permits analysis of the likely role of the residues inthe functioning of the candidate immunoglobulin sequence, i.e., theanalysis of residues that influence the ability of the candidateimmunoglobulin to bind its antigen. In this way, FR residues can beselected and combined from the recipient and import sequences so thatthe desired antibody characteristic, such as increased affinity for thetarget antigen(s), is achieved. In general, the hypervariable regionresidues are directly and most substantially involved in influencingantigen binding.

(iv) Human Antibodies

As an alternative to humanization, human antibodies can be generated.For example, it is now possible to produce transgenic animals (e.g.,mice) that are capable, upon immunization, of producing a fullrepertoire of human antibodies in the absence of endogenousimmunoglobulin production. For example, it has been described that thehomozygous deletion of the antibody heavy-chain joining region (J_(H))gene in chimeric and germ-line mutant mice results in completeinhibition of endogenous antibody production. Transfer of the humangerm-line immunoglobulin gene array in such germ-line mutant mice willresult in the production of human antibodies upon antigen challenge.See, e.g., Jakobovits et al., Proc. Natl. Acad. Sci. USA, 90:2551(1993); Jakobovits et al., Nature, 362:255-258 (1993); Bruggermann etal., Year in Immuno., 7:33 (1993); and U.S. Pat. Nos. 5,591,669,5,589,369 and 5,545,807.

Alternatively, phage display technology (McCafferty et al., Nature348:552-553 (1990)) can be used to produce human antibodies and antibodyfragments in vitro, from immunoglobulin variable (V) domain generepertoires from unimmunized donors. According to this technique,antibody V domain genes are cloned in-frame into either a major or minorcoat protein gene of a filamentous bacteriophage, such as M13 or fd, anddisplayed as functional antibody fragments on the surface of the phageparticle. Because the filamentous particle contains a single-strandedDNA copy of the phage genome, selections based on the functionalproperties of the antibody also result in selection of the gene encodingthe antibody exhibiting those properties. Thus, the phage mimics some ofthe properties of the B cell. Phage display can be performed in avariety of formats; for their review see, e.g., Johnson, Kevin S. andChiswell, David J., Current Opinion in Structural Biology 3:564-571(1993). Several sources of V-gene segments can be used for phagedisplay. Clackson et al., Nature, 352:624-628 (1991) isolated a diversearray of anti-oxazolone antibodies from a small random combinatoriallibrary of V genes derived from the spleens of immunized mice. Arepertoire of V genes from unimmunized human donors can be constructedand antibodies to a diverse array of antigens (including self-antigens)can be isolated essentially following the techniques described by Markset al., J. Mol. Biol. 222:581-597 (1991), or Griffith et al., EMBO J.12:725-734 (1993). See, also, U.S. Pat. Nos. 5,565,332 and 5,573,905.

Human antibodies may also be generated by in vitro activated B cells(see U.S. Pat. Nos. 5,567,610 and 5,229,275).

(v) Antibody Fragments

Various techniques have been developed for the production of antibodyfragments. Traditionally, these fragments were derived via proteolyticdigestion of intact antibodies (see, e.g., Morimoto et al., Journal ofBiochemical and Biophysical Methods 24:107-117 (1992) and Brennan etal., Science, 229:81 (1985)). However, these fragments can now beproduced directly by recombinant host cells. For example, the antibodyfragments can be isolated from the antibody phage libraries discussedabove. Alternatively, Fab′-SH fragments can be directly recovered fromE. coli and chemically coupled to form F(ab′)₂ fragments (Carter et al.,Bio/Technology 10:163-167 (1992)). According to another approach,F(ab′)₂ fragments can be isolated directly from recombinant host cellculture. Other techniques for the production of antibody fragments willbe apparent to the skilled practitioner. In other embodiments, theantibody of choice is a single chain Fv fragment (scFv). See WO93/16185; U.S. Pat. No. 5,571,894; and U.S. Pat. No. 5,587,458. Theantibody fragment may also be a “linear antibody”, e.g., as described inU.S. Pat. No. 5,641,870 for example. Such linear antibody fragments maybe monospecific or bispecific.

(vi) Bispecific Antibodies

Bispecific antibodies are antibodies that have binding specificities forat least two different epitopes. Exemplary bispecific antibodies maybind to two different epitopes of the B cell surface marker. Other suchantibodies may bind a first B cell marker and further bind a second Bcell surface marker. Alternatively, an anti-B cell marker binding armmay be combined with an arm which binds to a triggering molecule on aleukocyte such as a T-cell receptor molecule (e.g. CD2 or CD3), or Fcreceptors for IgG (FcγR), such as FcγRI (CD64), FcγRII (CD32) andFcγRIII (CD16) so as to focus cellular defense mechanisms to the B cell.Bispecific antibodies may also be used to localize cytotoxic agents tothe B cell. These antibodies possess a B cell marker-binding arm and anarm which binds the cytotoxic agent (e.g. saporin, anti-interferon-α,vinca alkaloid, ricin A chain, methotrexate or radioactive isotopehapten). Bispecific antibodies can be prepared as full length antibodiesor antibody fragments (e.g. F(ab′)₂ bispecific antibodies).

Methods for making bispecific antibodies are known in the art.Traditional production of full length bispecific antibodies is based onthe coexpression of two immunoglobulin heavy chain-light chain pairs,where the two chains have different specificities (Millstein et al.,Nature, 305:537-539 (1983)). Because of the random assortment ofimmunoglobulin heavy and light chains, these hybridomas (quadromas)produce a potential mixture of 10 different antibody molecules, of whichonly one has the correct bispecific structure. Purification of thecorrect molecule, which is usually done by affinity chromatographysteps, is rather cumbersome, and the product yields are low. Similarprocedures are disclosed in WO 93/08829, and in Traunecker et al., EMBOJ., 10:3655-3659 (1991).

According to a different approach, antibody variable domains with thedesired binding specificities (antibody-antigen combining sites) arefused to immunoglobulin constant domain sequences. The fusion preferablyis with an immunoglobulin heavy chain constant domain, comprising atleast part of the hinge, CH1 and CH3 regions. It is preferred to havethe first heavy-chain constant region (CH1) containing the sitenecessary for light chain binding, present in at least one of thefusions. DNAs encoding the immunoglobulin heavy chain fusions and, ifdesired, the immunoglobulin light chain, are inserted into separateexpression vectors, and are co-transfected into a suitable hostorganism. This provides for great flexibility in adjusting the mutualproportions of the three polypeptide fragments in embodiments whenunequal ratios of the three polypeptide chains used in the constructionprovide the optimum yields. It is, however, possible to insert thecoding sequences for two or all three polypeptide chains in oneexpression vector when the expression of at least two polypeptide chainsin equal ratios results in high yields or when the ratios are of noparticular significance.

In a preferred embodiment of this approach, the bispecific antibodiesare composed of a hybrid immunoglobulin heavy chain with a first bindingspecificity in one arm, and a hybrid immunoglobulin heavy chain-lightchain pair (providing a second binding specificity) in the other arm. Itwas found that this asymmetric structure facilitates the separation ofthe desired bispecific compound from unwanted immunoglobulin chaincombinations, as the presence of an immunoglobulin light chain in onlyone half of the bispecific molecule provides for a facile way ofseparation. This approach is disclosed in WO 94/04690. For furtherdetails of generating bispecific antibodies see, for example, Suresh etal., Methods in Enzymology, 121:210 (1986).

According to another approach described in U.S. Pat. No. 5,731,168, theinterface between a pair of antibody molecules can be engineered tomaximize the percentage of heterodimers which are recovered fromrecombinant cell culture. The preferred interface comprises at least apart of the C_(H)3 domain of an antibody constant domain. In thismethod, one or more small amino acid side chains from the interface ofthe first antibody molecule are replaced with larger side chains (e.g.tyrosine or tryptophan). Compensatory “cavities” of identical or similarsize to the large side chain(s) are created on the interface of thesecond antibody molecule by replacing large amino acid side chains withsmaller ones (e.g. alanine or threonine). This provides a mechanism forincreasing the yield of the heterodimer over other unwanted end-productssuch as homodimers.

Bispecific antibodies include cross-linked or “heteroconjugate”antibodies. For example, one of the antibodies in the heteroconjugatecan be coupled to avidin, the other to biotin. Such antibodies have, forexample, been proposed to target immune system cells to unwanted cells(U.S. Pat. No. 4,676,980), and for treatment of HIV infection (WO91/00360, WO 92/200373, and EP 03089). Heteroconjugate antibodies may bemade using any convenient cross-linking methods. Suitable cross-linkingagents are well known in the art, and are disclosed in U.S. Pat. No.4,676,980, along with a number of cross-linking techniques.

Techniques for generating bispecific antibodies from antibody fragmentshave also been described in the literature. For example, bispecificantibodies can be prepared using chemical linkage. Brennan et al.,Science, 229: 81 (1985) describe a procedure wherein intact antibodiesare proteolytically cleaved to generate F(ab′)₂ fragments. Thesefragments are reduced in the presence of the dithiol complexing agentsodium arsenite to stabilize vicinal dithiols and prevent intermoleculardisulfide formation. The Fab′ fragments generated are then converted tothionitrobenzoate (TNB) derivatives. One of the Fab′-TNB derivatives isthen reconverted to the Fab′-thiol by reduction with mercaptoethylamineand is mixed with an equimolar amount of the other Fab′-TNB derivativeto form the bispecific antibody. The bispecific antibodies produced canbe used as agents for the selective immobilization of enzymes.

Recent progress has facilitated the direct recovery of Fab′-SH fragmentsfrom E. coli, which can be chemically coupled to form bispecificantibodies. Shalaby et al., J. Exp. Med., 175: 217-225 (1992) describethe production of a fully humanized bispecific antibody F(ab′)₂molecule. Each Fab′ fragment was separately secreted from E. coli andsubjected to directed chemical coupling in vitro to form the bispecificantibody. The bispecific antibody thus formed was able to bind to cellsoverexpressing the ErbB2 receptor and normal human T cells, as well astrigger the lytic activity of human cytotoxic lymphocytes against humanbreast tumor targets.

Various techniques for making and isolating bispecific antibodyfragments directly from recombinant cell culture have also beendescribed. For example, bispecific antibodies have been produced usingleucine zippers. Kostelny et al., J. Immunol., 148(5):1547-1553 (1992).The leucine zipper peptides from the Fos and Jun proteins were linked tothe Fab′ portions of two different antibodies by gene fusion. Theantibody homodimers were reduced at the hinge region to form monomersand then re-oxidized to form the antibody heterodimers. This method canalso be utilized for the production of antibody homodimers. The“diabody” technology described by Hollinger et al., Proc. Natl. Acad.Sci. USA, 90:6444-6448 (1993) has provided an alternative mechanism formaking bispecific antibody fragments. The fragments comprise aheavy-chain variable domain (V_(H)) connected to a light-chain variabledomain (V_(L)) by a linker which is too short to allow pairing betweenthe two domains on the same chain. Accordingly, the V_(H) and V_(L)domains of one fragment are forced to pair with the complementary V_(L)and V_(H) domains of another fragment, thereby forming twoantigen-binding sites. Another strategy for making bispecific antibodyfragments by the use of single-chain Fv (sFv) dimers has also beenreported. See Gruber et al., J. Immunol., 152:5368 (1994).

Antibodies with more than two valencies are contemplated. For example,trispecific antibodies can be prepared. Tutt et al. J. Immunol. 147: 60(1991).

III. Conjugates and Other Modifications of the Antagonist

The antagonist used in the methods or included in the articles ofmanufacture herein is optionally conjugated to a cytotoxic agent.

Chemotherapeutic agents useful in the generation of suchantagonist-cytotoxic agent conjugates have been described above.

Conjugates of an antagonist and one or more small molecule toxins, suchas a calicheamicin, a maytansine (U.S. Pat. No. 5,208,020), atrichothene, and CC 1065 are also contemplated herein. In one embodimentof the invention, the antagonist is conjugated to one or more maytansinemolecules (e.g. about 1 to about 10 maytansine molecules per antagonistmolecule). Maytansine may, for example, be converted to May-SS-Me whichmay be reduced to May-SH3 and reacted with modified antagonist (Chari etal. Cancer Research 52: 127-131 (1992)) to generate amaytansinoid-antagonist conjugate.

Alternatively, the antagonist is conjugated to one or more calicheamicinmolecules. The calicheamicin family of antibiotics are capable ofproducing double-stranded DNA breaks at sub-picomolar concentrations.Structural analogues of calicheamicin which may be used include, but arenot limited to, γ₁ ^(I), α₂ ^(I), α₃ ^(I), N-acetyl-γ₁ ^(I), PSAG andθ^(I) ₁ (Hinman et al. Cancer Research 53: 3336-3342 (1993) and Lode etal. Cancer Research 58: 2925-2928 (1998)).

Enzymatically active toxins and fragments thereof which can be usedinclude diphtheria A chain, nonbinding active fragments of diphtheriatoxin, exotoxin A chain (from Pseudomonas aeruginosa), ricin A chain,abrin A chain, modeccin A chain, alpha-sarcin, Aleurites fordiiproteins, dianthin proteins, Phytolaca americana proteins (PAPI, PAPII,and PAP-S), momordica charantia inhibitor, curcin, crotin, sapaonariaofficinalis inhibitor, gelonin, mitogellin, restrictocin, phenomycin,enomycin and the tricothecenes. See, for example, WO 93/21232 publishedOct. 28, 1993.

The present invention further contemplates antagonist conjugated with acompound with nucleolytic activity (e.g. a ribonuclease or a DNAendonuclease such as a deoxyribonuclease; DNase).

A variety of radioactive isotopes are available for the production ofradioconjugated antagonists. Examples include At²¹¹, I¹³¹, I¹²⁵, Y⁹⁰,Re¹⁸⁶, Re¹⁸⁸, Sm¹⁵³, Bi²¹², P³² and radioactive isotopes of Lu.

Conjugates of the antagonist and cytotoxic agent may be made using avariety of bifunctional protein coupling agents such asN-succinimidyl-3-(2-pyridyldithiol) propionate (SPDP),succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate,iminothiolane (IT), bifunctional derivatives of imidoesters (such asdimethyl adipimidate HCL), active esters (such as disuccinimidylsuberate), aldehydes (such as glutareldehyde), bis-azido compounds (suchas bis (p-azidobenzoyl) hexanediamine), bis-diazonium derivatives (suchas bis-(p-diazoniumbenzoyl)-ethylenediamine), diisocyanates (such astolyene 2,6-diisocyanate), and bis-active fluorine compounds (such as1,5-difluoro-2,4-dinitrobenzene). For example, a ricin immunotoxin canbe prepared as described in Vitetta et al. Science 238: 1098 (1987).Carbon-14-labeled 1-isothiocyanatobenzyl-3-methyldiethylenetriaminepentaacetic acid (MX-DTPA) is an exemplary chelating agent forconjugation of radionucleotide to the antagonist. See WO94/11026. Thelinker may be a “cleavable linker” facilitating release of the cytotoxicdrug in the cell. For example, an acid-labile linker,peptidase-sensitive linker, dimethyl linker or disulfide-containinglinker (Chari et al. Cancer Research 52: 127-131 (1992)) may be used.

Alternatively, a fusion protein comprising the antagonist and cytotoxicagent may be made, e.g. by recombinant techniques or peptide synthesis.

In yet another embodiment, the antagonist may be conjugated to a“receptor” (such streptavidin) for utilization in tumor pretargetingwherein the antagonist-receptor conjugate is administered to thepatient, followed by removal of unbound conjugate from the circulationusing a clearing agent and then administration of a “ligand” (e.g.avidin) which is conjugated to a cytotoxic agent (e.g. aradionucleotide).

The antagonists of the present invention may also be conjugated with aprodrug-activating enzyme which converts a prodrug (e.g. a peptidylchemotherapeutic agent, see WO81/01145) to an active anti-cancer drug.See, for example, WO 88/07378 and U.S. Pat. No. 4,975,278.

The enzyme component of such conjugates includes any enzyme capable ofacting on a prodrug in such a way so as to covert it into its moreactive, cytotoxic form.

Enzymes that are useful in the method of this invention include, but arenot limited to, alkaline phosphatase useful for convertingphosphate-containing prodrugs into free drugs; arylsulfatase useful forconverting sulfate-containing prodrugs into free drugs; cytosinedeaminase useful for converting non-toxic 5-fluorocytosine into theanti-cancer drug, 5-fluorouracil; proteases, such as serratia protease,thermolysin, subtilisin, carboxypeptidases and cathepsins (such ascathepsins B and L), that are useful for converting peptide-containingprodrugs into free drugs; D-alanylcarboxypeptidases, useful forconverting prodrugs that contain D-amino acid substituents;carbohydrate-cleaving enzymes such as β-galactosidase and neuraminidaseuseful for converting glycosylated prodrugs into free drugs; β-lactamaseuseful for converting drugs derivatized with β-lactams into free drugs;and penicillin amidases, such as penicillin V amidase or penicillin Gamidase, useful for converting drugs derivatized at their aminenitrogens with phenoxyacetyl or phenylacetyl groups, respectively, intofree drugs. Alternatively, antibodies with enzymatic activity, alsoknown in the art as “abzymes”, can be used to convert the prodrugs ofthe invention into free active drugs (see, e.g., Massey, Nature 328:457-458 (1987)). Antagonist-abzyme conjugates can be prepared asdescribed herein for delivery of the abzyme to a tumor cell population.

The enzymes of this invention can be covalently bound to the antagonistby techniques well known in the art such as the use of theheterobifunctional crosslinking reagents discussed above. Alternatively,fusion proteins comprising at least the antigen binding region of anantagonist of the invention linked to at least a functionally activeportion of an enzyme of the invention can be constructed usingrecombinant DNA techniques well known in the art (see, e.g., Neubergeret al., Nature, 312: 604-608 (1984)).

Other modifications of the antagonist are contemplated herein. Forexample, the antagonist may be linked to one of a variety ofnonproteinaceous polymers, e.g., polyethylene glycol, polypropyleneglycol, polyoxyalkylenes, or copolymers of polyethylene glycol andpolypropylene glycol.

The antagonists disclosed herein may also be formulated as liposomes.Liposomes containing the antagonist are prepared by methods known in theart, such as described in Epstein et al., Proc. Natl. Acad. Sci. USA,82:3688 (1985); Hwang et al., Proc. Natl. Acad. Sci. USA, 77:4030(1980); U.S. Pat. Nos. 4,485,045 and 4,544,545; and WO97/38731 publishedOct. 23, 1997. Liposomes with enhanced circulation time are disclosed inU.S. Pat. No. 5,013,556.

Particularly useful liposomes can be generated by the reverse phaseevaporation method with a lipid composition comprisingphosphatidylcholine, cholesterol and PEG-derivatizedphosphatidylethanolamine (PEG-PE). Liposomes are extruded throughfilters of defined pore size to yield liposomes with the desireddiameter. Fab′ fragments of an antibody of the present invention can beconjugated to the liposomes as described in Martin et al. J. Biol. Chem.257: 286-288 (1982) via a disulfide interchange reaction. Achemotherapeutic agent is optionally contained within the liposome. SeeGabizon et al. J. National Cancer Inst. 81(19)1484 (1989).

Amino acid sequence modification(s) of protein or peptide antagonistsdescribed herein are contemplated. For example, it may be desirable toimprove the binding affinity and/or other biological properties of theantagonist. Amino acid sequence variants of the antagonist are preparedby introducing appropriate nucleotide changes into the antagonistnucleic acid, or by peptide synthesis. Such modifications include, forexample, deletions from, and/or insertions into and/or substitutions of,residues within the amino acid sequences of the antagonist. Anycombination of deletion, insertion, and substitution is made to arriveat the final construct, provided that the final construct possesses thedesired characteristics. The amino acid changes also may alterpost-translational processes of the antagonist, such as changing thenumber or position of glycosylation sites.

A useful method for identification of certain residues or regions of theantagonist that are preferred locations for mutagenesis is called“alanine scanning mutagenesis” as described by Cunningham and WellsScience, 244:1081-1085 (1989). Here, a residue or group of targetresidues are identified (e.g., charged residues such as arg, asp, his,lys, and glu) and replaced by a neutral or negatively charged amino acid(most preferably alanine or polyalanine) to affect the interaction ofthe amino acids with antigen. Those amino acid locations demonstratingfunctional sensitivity to the substitutions then are refined byintroducing further or other variants at, or for, the sites ofsubstitution. Thus, while the site for introducing an amino acidsequence variation is predetermined, the nature of the mutation per seneed not be predetermined. For example, to analyze the performance of amutation at a given site, ala scanning or random mutagenesis isconducted at the target codon or region and the expressed antagonistvariants are screened for the desired activity.

Amino acid sequence insertions include amino- and/or carboxyl-terminalfusions ranging in length from one residue to polypeptides containing ahundred or more residues, as well as intrasequence insertions of singleor multiple amino acid residues. Examples of terminal insertions includean antagonist with an N-terminal methionyl residue or the antagonistfused to a cytotoxic polypeptide. Other insertional variants of theantagonist molecule include the fusion to the N- or C-terminus of theantagonist of an enzyme, or a polypeptide which increases the serumhalf-life of the antagonist.

Another type of variant is an amino acid substitution variant. Thesevariants have at least one amino acid residue in the antagonist moleculereplaced by different residue. The sites of greatest interest forsubstitutional mutagenesis of antibody antagonists include thehypervariable regions, but FR alterations are also contemplated.Conservative substitutions are shown in Table 1 under the heading of“preferred substitutions”. If such substitutions result in a change inbiological activity, then more substantial changes, denominated“exemplary substitutions” in Table 1, or as further described below inreference to amino acid classes, may be introduced and the productsscreened.

TABLE 1 Original Preferred Residue Exemplary Substitutions SubstitutionsAla (A) val; leu; ile val Arg (R) lys; gln; asn lys Asn (N) gln; his;asp, lys; arg gln Asp (D) glu; asn glu Cys (C) ser; ala ser Gln (Q) asn;glu asn Glu (E) asp; gln asp Gly (G) ala ala His (H) asn; gln; lys; argarg Ile (I) leu; val; met; ala; leu phe; norleucine Leu (L) norleucine;ile; val; ile met; ala; phe Lys (K) arg; gln; asn arg Met (M) leu; phe;ile leu Phe (F) leu; val; ile; ala; tyr tyr Pro (P) ala ala Ser (5) thrthr Thr (T) ser ser Trp (W) tyr; phe tyr Tyr (Y) trp; phe; thr; ser pheVal (V) ile; leu; met; phe; leu ala; norleucine

Substantial modifications in the biological properties of the antagonistare accomplished by selecting substitutions that differ significantly intheir effect on maintaining (a) the structure of the polypeptidebackbone in the area of the substitution, for example, as a sheet orhelical conformation, (b) the charge or hydrophobicity of the moleculeat the target site, or (c) the bulk of the side chain. Naturallyoccurring residues are divided into groups based on common side-chainproperties:

(1) hydrophobic: norleucine, met, ala, val, leu, ile;

(2) neutral hydrophilic: cys, ser, thr;

(3) acidic: asp, glu;

(4) basic: asn, gln, his, lys, arg;

(5) residues that influence chain orientation: gly, pro; and

(6) aromatic: trp, tyr, phe.

Non-conservative substitutions will entail exchanging a member of one ofthese classes for another class.

Any cysteine residue not involved in maintaining the proper conformationof the antagonist also may be substituted, generally with serine, toimprove the oxidative stability of the molecule and prevent aberrantcrosslinking. Conversely, cysteine bond(s) may be added to theantagonist to improve its stability (particularly where the antagonistis an antibody fragment such as an Fv fragment).

A particularly preferred type of substitutional variant involvessubstituting one or more hypervariable region residues of a parentantibody. Generally, the resulting variant(s) selected for furtherdevelopment will have improved biological properties relative to theparent antibody from which they are generated. A convenient way forgenerating such substitutional variants is affinity maturation usingphage display. Briefly, several hypervariable region sites (e.g. 6-7sites) are mutated to generate all possible amino substitutions at eachsite. The antibody variants thus generated are displayed in a monovalentfashion from filamentous phage particles as fusions to the gene IIIproduct of M13 packaged within each particle. The phage-displayedvariants are then screened for their biological activity (e.g. bindingaffinity) as herein disclosed. In order to identify candidatehypervariable region sites for modification, alanine scanningmutagenesis can be performed to identify hypervariable region residuescontributing significantly to antigen binding. Alternatively, or inadditionally, it may be beneficial to analyze a crystal structure of theantigen-antibody complex to identify contact points between the antibodyand antigen. Such contact residues and neighboring residues arecandidates for substitution according to the techniques elaboratedherein. Once such variants are generated, the panel of variants issubjected to screening as described herein and antibodies with superiorproperties in one or more relevant assays may be selected for furtherdevelopment.

Another type of amino acid variant of the antagonist alters the originalglycosylation pattern of the antagonist. By altering is meant deletingone or more carbohydrate moieties found in the antagonist, and/or addingone or more glycosylation sites that are not present in the antagonist.

Glycosylation of polypeptides is typically either N-linked or O-linked.N-linked refers to the attachment of the carbohydrate moiety to the sidechain of an asparagine residue. The tripeptide sequencesasparagine-X-serine and asparagine-X-threonine, where X is any aminoacid except proline, are the recognition sequences for enzymaticattachment of the carbohydrate moiety to the asparagine side chain.Thus, the presence of either of these tripeptide sequences in apolypeptide creates a potential glycosylation site. O-linkedglycosylation refers to the attachment of one of the sugarsN-aceylgalactosamine, galactose, or xylose to a hydroxyamino acid, mostcommonly serine or threonine, although 5-hydroxyproline or5-hydroxylysine may also be used.

Addition of glycosylation sites to the antagonist is convenientlyaccomplished by altering the amino acid sequence such that it containsone or more of the above-described tripeptide sequences (for N-linkedglycosylation sites). The alteration may also be made by the additionof, or substitution by, one or more serine or threonine residues to thesequence of the original antagonist (for O-linked glycosylation sites).

Nucleic acid molecules encoding amino acid sequence variants of theantagonist are prepared by a variety of methods known in the art. Thesemethods include, but are not limited to, isolation from a natural source(in the case of naturally occurring amino acid sequence variants) orpreparation by oligonucleotide-mediated (or site-directed) mutagenesis,PCR mutagenesis, and cassette mutagenesis of an earlier prepared variantor a non-variant version of the antagonist.

It may be desirable to modify the antagonist of the invention withrespect to effector function, e.g. so as to enhance antigen-dependentcell-mediated cyotoxicity (ADCC) and/or complement dependentcytotoxicity (CDC) of the antagonist. This may be achieved byintroducing one or more amino acid substitutions in an Fc region of anantibody antagonist. Alternatively or additionally, cysteine residue(s)may be introduced in the Fc region, thereby allowing interchaindisulfide bond formation in this region. The homodimeric antibody thusgenerated may have improved internalization capability and/or increasedcomplement-mediated cell killing and antibody-dependent cellularcytotoxicity (ADCC). See Caron et al., J. Exp Med. 176:1191-1195 (1992)and Shopes, B. J. Immunol. 148:2918-2922 (1992). Homodimeric antibodieswith enhanced anti-tumor activity may also be prepared usingheterobifunctional cross-linkers as described in Wolff et al. CancerResearch 53:2560-2565 (1993). Alternatively, an antibody can beengineered which has dual Fc regions and may thereby have enhancedcomplement lysis and ADCC capabilities. See Stevenson et al. Anti-CancerDrug Design 3:219-230 (1989).

To increase the serum half life of the antagonist, one may incorporate asalvage receptor binding epitope into the antagonist (especially anantibody fragment) as described in U.S. Pat. No. 5,739,277, for example.As used herein, the term “salvage receptor binding epitope” refers to anepitope of the Fc region of an IgG molecule (e.g., IgG₁, IgG₂, IgG₃, orIgG₄) that is responsible for increasing the in vivo serum half-life ofthe IgG molecule.

IV. Pharmaceutical Formulations

Therapeutic formulations of the antagonists used in accordance with thepresent invention are prepared for storage by mixing an antagonisthaving the desired degree of purity with optional pharmaceuticallyacceptable carriers, excipients or stabilizers (Remington'sPharmaceutical Sciences 16th edition, Osol, A. Ed. (1980)), in the formof lyophilized formulations or aqueous solutions. Acceptable carriers,excipients, or stabilizers are nontoxic to recipients at the dosages andconcentrations employed, and include buffers such as phosphate, citrate,and other organic acids; antioxidants including ascorbic acid andmethionine; preservatives (such as octadecyldimethylbenzyl ammoniumchloride; hexamethonium chloride; benzalkonium chloride, benzethoniumchloride; phenol, butyl or benzyl alcohol; alkyl parabens such as methylor propyl paraben; catechol; resorcinol; cyclohexanol; 3-pentanol; andm-cresol); low molecular weight (less than about 10 residues)polypeptides; proteins, such as serum albumin, gelatin, orimmunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone;amino acids such as glycine, glutamine, asparagine, histidine, arginine,or lysine; monosaccharides, disaccharides, and other carbohydratesincluding glucose, mannose, or dextrins; chelating agents such as EDTA;sugars such as sucrose, mannitol, trehalose or sorbitol; salt-formingcounter-ions such as sodium; metal complexes (e.g. Zn-proteincomplexes); and/or non-ionic surfactants such as TWEEN™, PLURONICS™ orpolyethylene glycol (PEG).

Exemplary anti-CD20 antibody formulations are described in WO98/56418,expressly incorporated herein by reference. This publication describes aliquid multidose formulation comprising 40 mg/mL rituximab, 25 mMacetate, 150 mM trehalose, 0.9% benzyl alcohol, 0.02% polysorbate 20 atpH 5.0 that has a minimum shelf life of two years storage at 2-8° C.Another anti-CD20 formulation of interest comprises 10 mg/mL rituximabin 9.0 mg/mL sodium chloride, 7.35 mg/mL sodium citrate dihydrate, 0.7mg/mL polysorbate 80, and Sterile Water for Injection, pH 6.5.

Lyophilized formulations adapted for subcutaneous administration aredescribed in WO97/04801. Such lyophilized formulations may bereconstituted with a suitable diluent to a high protein concentrationand the reconstituted formulation may be administered subcutaneously tothe mammal to be treated herein.

The formulation herein may also contain more than one active compound asnecessary for the particular indication being treated, preferably thosewith complementary activities that do not adversely affect each other.For example, it may be desirable to further provide a cytotoxic agent,chemotherapeutic agent, cytokine or immunosuppressive agent (e.g. onewhich acts on T cells, such as cyclosporin or an antibody that binds Tcells, e.g. one which binds LFA-1). The effective amount of such otheragents depends on the amount of antagonist present in the formulation,the type of disease or disorder or treatment, and other factorsdiscussed above. These are generally used in the same dosages and withadministration routes as used hereinbefore or about from 1 to 99% of theheretofore employed dosages.

The active ingredients may also be entrapped in microcapsules prepared,for example, by coacervation techniques or by interfacialpolymerization, for example, hydroxymethylcellulose orgelatin-microcapsules and poly-(methylmethacylate) microcapsules,respectively, in colloidal drug delivery systems (for example,liposomes, albumin microspheres, microemulsions, nano-particles andnanocapsules) or in macroemulsions. Such techniques are disclosed inRemington's Pharmaceutical Sciences 16th edition, Osol, A. Ed. (1980).

Sustained-release preparations may be prepared. Suitable examples ofsustained-release preparations include semipermeable matrices of solidhydrophobic polymers containing the antagonist, which matrices are inthe form of shaped articles, e.g. films, or microcapsules. Examples ofsustained-release matrices include polyesters, hydrogels (for example,poly(2-hydroxyethyl-methacrylate), or poly(vinylalcohol)), polylactides(U.S. Pat. No. 3,773,919), copolymers of L-glutamic acid and γethyl-L-glutamate, non-degradable ethylene-vinyl acetate, degradablelactic acid-glycolic acid copolymers such as the LUPRON DEPOT™(injectable microspheres composed of lactic acid-glycolic acid copolymerand leuprolide acetate), and poly-D-(−)-3-hydroxybutyric acid.

The formulations to be used for in vivo administration must be sterile.This is readily accomplished by filtration through sterile filtrationmembranes.

V. Treatment with the Antagonist

The present invention concerns therapy of a subpopulation of mammals,especially humans, with, or susceptible to, an autoimmune disease, whoexperience an inadequate response to previous or current treatment witha TNFα-inhibitor. Generally, the mammal to be treated herein will beidentified following therapy with one or more treatments with one ormore TNFα-inhibitor(s) such as Etanercept (ENBREL®), Infliximab(REMICADE®) or Adalimumab (HUMIRA™), as experiencing an inadequateresponse to previous or current treatment with a TNFα-inhibitor becauseof toxicity and/or inadequate efficacy. However, the invention is notlimited to a prior therapy step with such a TNFα-inhibitor; forinstance, the patient may be considered to be prone to experience atoxicity, e.g. cardiac toxicity, with a TNFα-inhibitor before therapytherewith has begun, or the patient may be determined to be one who isunlikely to respond to therapy with a TNFα-inhibitor.

The various autoimmune diseases to be treated herein are listed in thedefinitions section above. The preferred indications herein arerheumatoid arthritis, psoriatic arthritis, or Crohn's disease.

Generally, the mammal treated herein will not be suffering from a B-cellmalignancy.

According to one embodiment of the invention contemplated herein, thetherapeutic approach will reduce negative side effects (such asinfections, heart failure and demyelination) associated with therapywith a TNFα-inhibitor.

The composition comprising an antagonist which binds to a B cell surfacemarker will be formulated, dosed, and administered in a fashionconsistent with good medical practice. Factors for consideration in thiscontext include the particular disease or disorder being treated, theparticular mammal being treated, the clinical condition of theindividual patient, the cause of the disease or disorder, the site ofdelivery of the agent, the method of administration, the scheduling ofadministration, and other factors known to medical practitioners. Thetherapeutically effective amount of the antagonist to be administeredwill be governed by such considerations.

As a general proposition, the therapeutically effective amount of theantagonist administered parenterally per dose will be in the range ofabout 0.1 to 20 mg/kg of patient body weight per day, with the typicalinitial range of antagonist used being in the range of about 2 to 10mg/kg.

The preferred antagonist is an antibody, e.g. an antibody such asRITUXAN®, which is not conjugated to a cytotoxic agent. Suitable dosagesfor an unconjugated antibody are, for example, in the range from about20 mg/m² to about 1000 mg/m². In one embodiment, the dosage of theantibody differs from that presently recommended for RITUXAN®. Forexample, one may administer to the patient one or more doses ofsubstantially less than 375 mg/m² of the antibody, e.g. where the doseis in the range from about 20 mg/m² to about 250 mg/m², for example fromabout 50 mg/m² to about 200 mg/m².

Exemplary dosage regimens include 375 mg/m2 weekly×4; or 1000 mg×2 (e.g.on days 1 and 15).

Moreover, one may administer one or more initial dose(s) of the antibodyfollowed by one or more subsequent dose(s), wherein the mg/m² dose ofthe antibody in the subsequent dose(s) exceeds the mg/m² dose of theantibody in the initial dose(s). For example, the initial dose may be inthe range from about 20 mg/m² to about 250 mg/m² (e.g. from about 50mg/m² to about 200 mg/m²) and the subsequent dose may be in the rangefrom about 250 mg/m² to about 1000 mg/m².

As noted above, however, these suggested amounts of antagonist aresubject to a great deal of therapeutic discretion. The key factor inselecting an appropriate dose and scheduling is the result obtained, asindicated above. For example, relatively higher doses may be neededinitially for the treatment of ongoing and acute diseases. To obtain themost efficacious results, depending on the disease or disorder, theantagonist is administered as close to the first sign, diagnosis,appearance, or occurrence of the disease or disorder as possible orduring remissions of the disease or disorder.

The antagonist is administered by any suitable means, includingparenteral, subcutaneous, intraperitoneal, intrapulmonary, andintranasal, and, if desired for local immunosuppressive treatment,intralesional administration. Parenteral infusions includeintramuscular, intravenous, intraarterial, intraperitoneal, orsubcutaneous administration. In addition, the antagonist may suitably beadministered by pulse infusion, e.g., with declining doses of theantagonist. Preferably the dosing is given by injections, mostpreferably intravenous or subcutaneous injections, depending in part onwhether the administration is brief or chronic.

One may administer other compounds, such as cytotoxic agents,chemotherapeutic agents, immunosuppressive agents and/or cytokines withthe antagonists herein. The combined administration includescoadministration, using separate formulations or a single pharmaceuticalformulation, and consecutive administration in either order, whereinpreferably there is a time period while both (or all) active agentssimultaneously exert their biological activities. For RA, and otherautoimmune diseases, the antagonist (e.g. CD20 antibody) may be combinedwith any one or more of disease-modifying antirheumatic drugs (DMARDs)such as hydroxycloroquine, sulfasalazine, methotrexate, leflunomide,azathioprine, D-penicillamine, Gold (oral), Gold (intramuscular),minocycline, cyclosporine, Staphylococcal protein A immunoadsorption;intravenous immunoglobulin (IVIG); nonsteroidal antiinflammatory drugs(NSAIDs); glucocorticoid (e.g. via joint injection); corticosteroid(e.g. methylprednisolone and/or prednisone); folate etc. Preferably, aTNFα-inhibitor is not administered to the mammal during the period oftreatment with the CD20 antagonist.

Aside from administration of protein antagonists to the patient thepresent application contemplates administration of antagonists by genetherapy. Such administration of nucleic acid encoding the antagonist isencompassed by the expression “administering a therapeutically effectiveamount of an antagonist”. See, for example, WO96/07321 published Mar.14, 1996 concerning the use of gene therapy to generate intracellularantibodies.

There are two major approaches to getting the nucleic acid (optionallycontained in a vector) into the patient's cells; in vivo and ex vivo.For in vivo delivery the nucleic acid is injected directly into thepatient, usually at the site where the antagonist is required. For exvivo treatment, the patient's cells are removed, the nucleic acid isintroduced into these isolated cells and the modified cells areadministered to the patient either directly or, for example,encapsulated within porous membranes which are implanted into thepatient (see, e.g. U.S. Pat. Nos. 4,892,538 and 5,283,187). There are avariety of techniques available for introducing nucleic acids intoviable cells. The techniques vary depending upon whether the nucleicacid is transferred into cultured cells in vitro, or in vivo in thecells of the intended host. Techniques suitable for the transfer ofnucleic acid into mammalian cells in vitro include the use of liposomes,electroporation, microinjection, cell fusion, DEAE-dextran, the calciumphosphate precipitation method, etc. A commonly used vector for ex vivodelivery of the gene is a retrovirus.

The currently preferred in vivo nucleic acid transfer techniques includetransfection with viral vectors (such as adenovirus, Herpes simplex Ivirus, or adeno-associated virus) and lipid-based systems (useful lipidsfor lipid-mediated transfer of the gene are DOTMA, DOPE and DC-Chol, forexample). In some situations it is desirable to provide the nucleic acidsource with an agent that targets the target cells, such as an antibodyspecific for a cell surface membrane protein or the target cell, aligand for a receptor on the target cell, etc. Where liposomes areemployed, proteins which bind to a cell surface membrane proteinassociated with endocytosis may be used for targeting and/or tofacilitate uptake, e.g. capsid proteins or fragments thereof tropic fora particular cell type, antibodies for proteins which undergointernalization in cycling, and proteins that target intracellularlocalization and enhance intracellular half-life. The technique ofreceptor-mediated endocytosis is described, for example, by Wu et al.,J. Biol. Chem. 262:4429-4432 (1987); and Wagner et al., Proc. Natl.Acad. Sci. USA 87:3410-3414 (1990). For review of the currently knowngene marking and gene therapy protocols see Anderson et al., Science256:808-813 (1992). See also WO 93/25673 and the references citedtherein.

Further details of the invention are illustrated by the followingnon-limiting Examples. The disclosures of all citations in thespecification are expressly incorporated herein by reference.

EXAMPLE 1

A patient with active rheumatoid arthritis who has an inadequateresponse to one or more TNFα-inhibitor therapies is treated with anantibody that binds the B-cell surface antigen, CD20.

Candidates for therapy according to this example include those who haveexperienced an inadequate response to previous or current treatment withetanercept, infliximab and/or adalimumab because of toxicity orinadequate efficacy (etanercept for ≧3 months at 25 mg twice a week orat least 4 infusions of infliximab at ≧3 mg/kg).

Patients may have swollen joint count (SJC)≧8 (66 joint count), andtender joint count (TJC)≧8 (68 joint count) at screening andrandomization; either CRP≧1.5 mg/dl (15 mg/L) or ESR≧28 mm/h; and/orradiographic evidence of at least one joint with definite erosionattributable to rheumatoid arthritis, as determined by the centralreading site (any joint of the hands, wrists or feet can be consideredwith the exception of the DIP joints of the hands).

The CD20 antibody used for therapy may be Rituximab (commerciallyavailable from Genentech, Inc.) or humanized 2H7 v16.

Patients are treated with a therapeutically effective dose of the CD20antibody, for instance, 1000 mg i.v. on Days 1 and 15, or 375 mg/m2 i.v.weekly×4.

Patients may also receive concomitant MTX (10-25 mg/week per oral (p.o.)or parenteral), together with a corticosteroid regimen consisting ofmethylprednisolone 100 mg i.v. 30 minutes prior to infusions of the CD20antibody and prednisone 60 mg p.o. on Days 2-7, 30 mg p.o. Days 8-14,returning to baseline dose by Day 16. Patients may also receive folate(5 mg/week) given as either a single dose or as divided daily doses.Patients optionally continue to receive any background corticosteroid(≦10 mg/d prednisone or equivalent) throughout the treatment period.

The primary endpoint may be the proportion of patients with an ACR20response at Week 24 using a Cochran-Mantel-Haenszel (CMH) test forcomparing group differences, adjusted for rheumatoid factor and region.

Potential secondary endpoints include:

1. Proportion of patients with ACR50 and 70 responses at Week 24. Thesemay be analyzed as specified for the primary endpoint.

2. Change in Disease Activity Score (DAS) from screening to Week 24.These may be assessed using an ANOVA model with baseline DAS, rheumatoidfactor, and treatment as terms in the model.

3. Categorical DAS responders (EULAR response) at Week 24. These may beassessed using a CMH test adjusted for rheumatoid factor.

4. Changes from screening in ACR core set (SJC, TJC, patient's andphysician's global assessments, HAQ, pain, CRP, and ESR). Descriptivestatistics may be reported for these parameters.

5. Changes from screening in SF-36. Descriptive statistics may bereported for the 8 domain scores and the mental and physical componentscores. In addition, the mental and physical component scores may befurther categorized and analyzed.

6. Change in modified Sharp radiographic total score, erosion score, andjoint space narrowing score. These may be analyzed using continuous orcategorical methodology, as appropriate.

Exploratory endpoints and analysis may involve:

ACR(20/50/70 and ACR n) and change in DAS responses over Weeks 8, 12,16, 20, 24 and beyond will be assessed using a binary or continuousrepeated measures model, as appropriate. Exploratory radiographicanalyses including proportion of patients with no erosive progressionmay be assessed at weeks 24 and beyond.

Further exploratory endpoints (for example complete clinical response,disease free period) will be analyzed descriptively as part of theextended observation period.

Changes from Screen in FACIT-F fatigue will be analyzed with descriptivestatistics.

Therapy of RA with the CD20 antibody in patients with an inadequateresponse to TNFα inhibitor therapy as described above will result in abeneficial clinical response according to any one or more of theendpoints noted above.

1. A method of treating an autoimmune disease in a mammal whoexperiences an inadequate response to a TNFα-inhibitor, comprisingadministering to the mammal a therapeutically effective amount of anantagonist which binds to a B cell surface marker.
 2. The method ofclaim 1 wherein the B cell surface marker is selected from the groupconsisting of CD10, CD19, CD20, CD21, CD22, CD23, CD24, CD37, CD40,CD53, CD72, CD73, CD74, CDw75, CDw76, CD77, CDw78, CD79a, CD79b, CD80,CD81, CD82, CD83, CDw84, CD85 and CD86.
 3. The method of claim 1 whereinthe antagonist comprises an antibody.
 4. The method of claim 3 whereinthe antibody binds CD20.
 5. The method of claim 1 wherein the autoimmunedisease is selected from the group consisting of arthritis, rheumatoidarthritis, juvenile rheumatoid arthritis, osteoarthritis, psoriaticarthritis, psoriasis, dermatitis, polymyositis/dermatomyositis, toxicepidermal necrolysis, systemic scleroderma and sclerosis, responsesassociated with inflammatory bowel disease, Crohn's disease, ulcerativecolitis, respiratory distress syndrome, adult respiratory distresssyndrome (ARDS), meningitis, encephalitis, uveitis, colitis,glomerulonephritis, allergic conditions, eczema, asthma, conditionsinvolving infiltration of T cells and chronic inflammatory responses,atherosclerosis, autoimmune myocarditis, leukocyte adhesion deficiency,systemic lupus erythematosus (SLE), juvenile onset diabetes, multiplesclerosis, allergic encephalomyelitis, immune responses associated withacute and delayed hypersensitivity mediated by cytokines andT-lymphocytes, tuberculosis, sarcoidosis, granulomatosis includingWegener's granulomatosis, agranulocytosis, vasculitis (including ANCA),aplastic anemia, Diamond Blackfan anemia, immune hemolytic anemiaincluding autoimmune hemolytic anemia (AIHA), pernicious anemia, purered cell aplasia (PRCA), Factor VIII deficiency, hemophilia A,autoimmune neutropenia, pancytopenia, leukopenia, diseases involvingleukocyte diapedesis, central nervous system (CNS) inflammatorydisorders, multiple organ injury syndrome, mysathenia gravis,antigen-antibody complex mediated diseases, anti-glomerular basementmembrane disease, anti-phospholipid antibody syndrome, allergicneuritis, Bechet disease, Castleman's syndrome, Goodpasture's syndrome,Lambert-Eaton Myasthenic Syndrome, Reynaud's syndrome, Sjorgen'ssyndrome, Stevens-Johnson syndrome, solid organ transplant rejection,graft versus host disease (GVHD), pemphigoid bullous, pemphigus,autoimmune polyendocrinopathies, Reiter's disease, stiff-man syndrome,giant cell arteritis, immune complex nephritis, IgA nephropathy, IgMpolyneuropathies or IgM mediated neuropathy, idiopathic thrombocytopenicpurpura (ITP), thrombotic throbocytopenic purpura (TTP), autoimmunethrombocytopenia, autoimmune disease of the testis and ovary includingautoimmune orchitis and oophoritis, primary hypothyroidism; autoimmuneendocrine diseases including autoimmune thyroiditis, chronic thyroiditis(Hashimoto's Thyroiditis), subacute thyroiditis, idiopathichypothyroidism, Addison's disease, Grave's disease, autoimmunepolyglandular syndromes (or polyglandular endocrinopathy syndromes),Type I diabetes also referred to as insulin-dependent diabetes mellitus(IDDM) and Sheehan's syndrome; autoimmune hepatitis, lymphoidinterstitial pneumonitis (HIV), bronchiolitis obliterans(non-transplant) vs NSIP, Guillain-Barre' Syndrome, large vesselvasculitis (including polymyalgia rheumatica and giant cell (Takayasu's)arteritis), medium vessel vasculitis (including Kawasaki's disease andpolyarteritis nodosa), ankylosing spondylitis, Berger's disease (IgAnephropathy), rapidly progressive glomerulonephritis, primary biliarycirrhosis, Celiac sprue (gluten enteropathy), cryoglobulinemia,amyotrophic lateral sclerosis (ALS), coronary artery disease.
 6. Themethod of claim 1 wherein the mammal is human.
 7. The method of claim 3wherein the antibody is not conjugated with a cytotoxic agent.
 8. Themethod of claim 4 wherein the antibody comprises rituximab.
 9. Themethod of claim 4 wherein the antibody comprises variable domains as inSEQ ID Nos. 1 &
 2. 10. The method of claim 3 wherein the antibody isconjugated with a cytotoxic agent.
 11. The method of claim 1 whichconsists essentially of administering the antagonist to the mammal. 12.A method of treating rheumatoid arthritis in a human patient whoexperiences an inadequate response to a TNFα-inhibitor, comprisingadministering to the patient a therapeutically effective amount of anantibody that binds to CD20.
 13. The method of claim 12 wherein theantibody comprises rituximab.
 14. The method of claim 12 wherein theantibody comprises variable domains as in SEQ ID Nos. 1 &
 2. 15. Themethod of claim 14 wherein the antibody comprises the light chain aminoacid sequence of SEQ ID No. 3 and the heavy chain amino acid sequence ofSEQ ID No.
 4. 16. The method of claim 12 wherein the antibody isadministered as two intravenous doses of 1000 mg.
 17. The method ofclaim 12 wherein the patient is further treated with concomitantmethotrexate (MTX).
 18. The method of claim 17 wherein the patient isfurther treated with a corticosteroid regimen.
 19. The method of claim18 wherein the corticosteroid regimen consists of methylprednisolone andprednisone.
 20. The method of claim 12 wherein the CD20 antibody is theonly B-cell surface marker antibody administered to the patient.
 21. Amethod of treating rheumatoid arthritis in a human patient whoexperiences an inadequate response to a TNFα-inhibitor, comprisingadministering to the patient two intravenous doses of 1000 mg of anantibody that binds to CD20.
 22. A method of treating rheumatoidarthritis in a human patient who experiences an inadequate response to aTNFα-inhibitor, comprising administering to the patient atherapeutically effective amount of an antibody that binds to CD20,wherein the antibody comprises variable domains as in SEQ ID Nos. 1 & 2.23. The method of claim 22 wherein the antibody comprises the lightchain amino acid sequence of SEQ ID No. 3 and the heavy chain amino acidsequence of SEQ ID No.
 4. 24. A method of treating rheumatoid arthritisin a human patient who experiences an inadequate response to aTNFα-inhibitor, comprising administering to the patient an antibodywhich binds to CD20 in an amount that is effective to provide an ACR50response at week 24, ACR70 response at week 24, or no erosiveprogression at weeks 24 and beyond.
 25. The method of claim 24 whereinthe antibody comprises rituximab.
 26. The method of claim 24 wherein theantibody comprises variable domains as in SEQ ID Nos. 1 &2.
 27. Themethod of claim 26 wherein the antibody comprises the light chain aminoacid sequence of SEQ ID No. 3 and the heavy chain amino acid sequence ofSEQ ID No.
 4. 28. The method of claim 24 wherein the antibody isadministered as two intravenous doses of 1000 mg.
 29. The method ofclaim 24 wherein the patient is further treated with concomitantmethotrexate (MTX).
 30. The method of claim 29 wherein the patient isfurther treated with a corticosteroid regimen.
 31. The method of claim30 wherein the corticosteroid regimen consists of methylprednisolone andprednisone.
 32. The method of claim 24 wherein the CD20 antibody is theonly B-cell surface marker antibody administered to the patient.
 33. Amethod of reducing the risk of a negative side effect selected from thegroup consisting of an infection, heart failure and demyelination,comprising administering to a mammal with an autoimmune disease atherapeutically effective amount of an antagonist which binds to a Bcell surface marker.